Anton Opanasenko, then 18, was one of the protesters on Kiev's Euromaidan ("European square"), fighting for Ukraine's independence from Russian influence among one million of his compatriots. He still remembers the excitement he felt in February 2014, when Ukraine's Revolution of Dignity succeed in forcing the pro-Kremlin president Yanukovych to flee. "We have protected our identity, retain ourselves, and remained who we are."

The Revolution of Dignity has initiated a revival of the Ukrainian national identification; however, it also angered the Kremlin. Soon after the revolution, Russia annexed Crimea and supported separatist in the Eastern part of Ukraine, plunging Eastern Ukraine into an ongoing war that led to the death of more than 10,000 people.

Russia would not tolerate Ukraine to develop its own national identity. "Russia has always believed that the Russians and the Ukrainians are one people, " Russian President Vladimir Putin stated after the annexation of Crimea. "I still think so now."

To Russia, Ukraine is an indispensable piece of the puzzle in the "Russkiy Mir" concept. Meaning "Russian World", this official Russian ideology aims at reinstating Russia as a regional and even global great power, and regaining control over a lost Ukraine.

The concept of "Russkiy Mir" (русский мир, Russian World) has been the dominating political ideology pushed forward by the Putin administration in the last few years, particularly salient in 2013-2014, when the Ukrainian "Revolution of Dignity" triggered a series of Russian military interventions in Ukraine.

Originally conceived to include the ethnic Russian diaspora in the newly independent post-Soviet states, the concept of "Russian World" has now been expanded to include Russian speakers, and even people of the former Soviet Union.

" Eurasian integration is a chance for the entire post-Soviet space to become an independent centre for global development, " described Putin: " rather than remaining on the outskirts of Europe and Asia."

Putin's ambition for Eurasian integration combined Russia's ambition to maintain a "sphere of influence" in the former Soviet countries and Russia's official effort to boost nationalist sentiments. Carrying these goals, "Russian World" serves as an idea that could lead Russia to re-emerge as a significant global great power, capable to compete with other great powers on the world stage.

The concept of "Russian World" did not emerge recently: it has been around as an official ideology ever since the disintegration of the USSR, but its connotation changed radically in the past 30 years, along with the change in Russia's view of the world order.

In the early stage of the Russian Republic, when the political leaders embrace the Western liberal democratic model and attempted to develop Russia as a member of the greater European civilisation and a reliable business partner. Originally, Russia hoped that the Russian diaspora of the "Russian World" would influence the homeland, bringing innovation and progressive values to Russia.

However, Russia became weary of Europe's "challenge" of its sphere of influence, particularly after the events of Orange Revolution of Ukraine in 2004, which Russia viewed as a result of EU and US's democracy promotion. The fact that Russia cannot be treated as an equal part in a US-led world order also became obvious. Riding on the decline of the superiority of the West since the mid-2000s', the Kremlin's track changed from embracing the Western liberal model to legitimizing its own authoritarian, state-capitalist model.

"The 'Russian World'...was an intellectual instrument proving that Russia, as a self-sufficient civilization, does not need any catch-up modernization, or any recognition from the West for that matter." described Mikhail Suslov, assistant professor of Cross-Cultural and Regional Studies at the University of Copenhagen.

To achieve this, the "Russian World" is envisaged as a cultural identity, imagining a community based on the Russian language, the Russian culture and the common glorious past. This is why Ukraine is essential to the "Russian World" identity.

Culturally, Russia, Ukraine and Belarus are descents of the same medieval federation of Kievan Rus', which originated in today's Ukrainian city of Kiev; as Putin put it, "Kiev is the mother of all Russian cities." The Kremlin is trying to own the cultural heritage of the Kievan Rus', defining Russia as its major successor and the others subordinating. Putin once described the Ukrainian language and Ukrainian culture as "part of our greater Russian, or Russian–Ukrainian, world".

Geopolitically, Ukraine is a buffer between Russia and the European Union essential for Russia's economic and military security. Renowned international relations scholar and former US national security adviser to President Jimmy Carter Zbigniew Brzezinski famously proclaimed in 1997 that "without Ukraine, Russia ceases to be a Eurasian empire."

Compared to other post-Soviet countries, Ukraine and Belarus are closest to Russia in cultural and historical terms. If Ukraine, one of the largest post-Soviet countries, is to deviate from the "Russian World" and opt for pursuing Euro-Atlantic integration, the "Russian World" rhetoric would be hard to hold together, and Russia's plan to establish economic and political unions in the post-Soviet regions would be difficult to gain real global influence.

"If Moscow regains control over Ukraine, Russia automatically again regains the wherewithal to become a powerful imperial state, spanning Europe and Asia." wrote Brzezinski.

Ever since Ukraine's independence from the USSR in 1991, the Kremlin has never ceased influencing Ukrainian politics through the pro-Russian politicians and parties in Ukraine, which has always been widely supported by the Ukrainian population: the presidency was held by pro-Russian politicians only for the exception between 2004-2010. In 2013, pro-Russian forces held 217 out of 450 seats in the Ukrainian parliament, Verkhovna Rada.

But the tight control of the Kremlin could not contain the longing for change in the hearts of the Ukrainian people. As the Kremlin pressured pro-Russian president Viktor Yanukovych to abandon an agreement with the EU in November 2013, hundreds of thousands of Ukrainians marched on the street. This "Revolution of Dignity" ended with Yanukovych fleeing the country and the election of a new, pro-European government.

During the revolution, the Ukrainian population experienced a monumental shift in how they understand themselves and their place in the world.

In 2012, only 68% of Ukrainian citizens viewed themselves as purely "Ukrainians", many others still saw themselves as partly Russians or entirely Russians. However, now over 80% would declare themselves only as Ukrainians. This trend of Ukrainian nationalism is evident even in ethnic Russian groups and Russian speakers: 75% and 83% of them now see Ukraine as their homeland, compared to only 50% and 66% in 2012.

This has translated into political preference in who Ukraine should be friends within the world. Before the revolution, more Ukrainians supported joining Russia-led region union than the EU, but this has since been reversed. Since 2014, Ukrainians supportive of joining the EU has rocketed to over 50%, while support for a Russian-led union fell below 20%.

The shift in both the national identity and foreign alliance preference of the Ukrainian people have fundamentally changed Ukrainian politics, as well as its relationship with Russia.

As the sentiment of Ukrainian voters turned against Russia, the Kremlin could no longer control Ukrainian politics through pro-Kremlin politicians and parties -- this channel of influence evaporated almost completely after the revolution. The pro-Russian forces have shrunk so much that they can no longer influence the mainstream political agenda: pro-Russian candidate can only marshall 12% support in the latest presidential election, and the number of seats in parliament diminished to only 29.

The Kremlin's control over Ukraine is significantly weakened. But it would not give up on its grab. Apart from the separatist war on the East, Ukraine is also suffering from Russian propagandistic infiltration, economic and trade blockade and cyber attacks.

The Kremlin is determined to keep Ukraine under its sphere of influence. At the celebration of the first anniversary of the seizure of Crimea, Putin restated his certainty that "Russian and Ukrainians are one people".

"Russians are reluctant to set Ukraine free as a nation of distinct and separate peoples," wrote Kremlinologist Lilia Shevtsova.

"For them, Ukraine is a woman who cheated on her husband (Russia), who is seduced by the West."

Maksym Yakovlyev, a political scientist at Kyiv-Mohyla Academy, studied Russian official propaganda and internet memes to understand the Russian propagandistic discourses regarding Ukraine. He found that Ukrainians are always portrayed as members of the same family with Russians, but hierarchically inferior.

"In Russian propaganda, Ukraine (as a woman) is always dependent, not taking its own decisions; in a patriarchal world, a woman cannot act on her own behalf. There must be somebody acting for her or seducing her."

The Kremlin rhetoric refused to recognize that Ukraine is switching path because of the people's will, framing it as manipulation of the EU and US. The post-revolution Ukrainian government has been branded as "neo-nazis" and "fascists" by the pro-Kremlin Russian media, denying its legitimacy.

The military and political war with Russia has dealt a heavy blow to Ukraine's economy, which depends on the Russian market before. But with the EU and the US increasing trade, opening more markets and providing financial aid packages with conditions to realize democratic and anti-corruption reforms, Ukraine has been gradually recovering. With a more diversified trade network and more efficient, transparency democratic institutions, Ukraine is building up its capacity to become a truly autonomous state, independent of Russian money, cultural and political influence.

In Russia, this is a manipulated betrayal. "So Ukraine was 'seduced' by the West with the promise of EU membership and a bright future...and cheated on Russia." Yakovlyev described in Russian propagandistic rhetoric.

By denying Ukraine's political agency and autonomy, the Kremlin is attempting to portray Ukraine as always dependent on either Russia or the West, incapable of having its own directions. Promoting a common identity under the "Russian World" concept, while Refusing to recognize Ukraine's distinct identity, is the Kremlin's attempt to retain Ukraine under its sphere of influence.

"The definition of Self as 'we' makes it possible for the second actor (Ukraine) to reinterpret their interests as compatible with the interests of the first actor (Russia), " Valentina Feklyunina, political scientist focusing on Russia, explained the rationale behind Russia's identity claim in her research.

Russia is persuading Ukraine to adopt its stance. "It is 'our' interests, rather than something imposed." Feklyunina wrote.

As Yakovlyev sees it, this attempt to render Russians and Ukrainians as "one people" with similar interests is what makes the Kremlin eager to obstruct Ukraine to develop Western liberal democracy, and to nullify Ukraine's political agency. Otherwise, the Russian regime may suffer a fatal backfire.

"For the Russia regime, it's very important that we fail in our reforms, " observed Yakovlyev. "Russia claims that liberal democracy is not feasible for Russia….if we succeed, this myth that Ukrainians and Russians are the same would hit them, that Russians can also have more democracy."

Anton is now a graduate student researching on Ukrainian history. As a history student, he understands very well that identities are only social constructs. Still, he proclaims himself to be a "Ukrainian nationalist".

"If we don't have an identity, illiberal countries like Russia would try to force their identity on us, " He explains his pursuit in Ukraine's history research. "Unless we have a stable identity, we cannot be independent and decide our future...the Russians will always try to overcome, to force, to subdue us to their values."

Anton firmly believes that Ukraine's future lies in building a liberal democracy, a system that is different from Russia's authoritarianism.