Nikita Krylov will return to the Ultimate Fighting Championship for the first time in nearly two years when he dukes it out with former KSW champion Jan Blachowicz in the UFC Fight Night 136 main event on Saturday at Olimpiysky Arena in Moscow. “The Miner” enters the cage on the strength of a four-fight winning streak that includes knockouts of Emanuel Newton and Fabio Maldonado.

As Krylov makes final preparations for his showdown with Blachowicz, here are five things you might not know about him:

1. He does not like calling people out.

Krylov is not a fan of challenging anyone, pointing to his belief that he will be compensated the same no matter who he faces. However, he said he is more than willing to scrap with anyone who calls him out. That is exactly what happened when he caught Blachowicz’s attention following a rear-naked choke submission of Francimar Barroso in May 2016. Instead, Krylov was given different opponents until he opted not to renew his contract with the UFC.

2. His childhood friend designed his chest tattoo.

Krylov has only one tattoo on his upper torso, and it is nothing less than special. The intricate black-and-grey ink was designed by a childhood friend who also doubled as his training partner for many years. Unfortunately, the friend was one of the casualties of the civil unrest in Ukraine a few years ago.

3. He comes from a family of miners.

Krylov got his nickname because his unbreakable will resembles that of a miner trapped a thousand meters below the surface and battling suffocation. He also actually comes from a family of miners in Donbass, Ukraine, and in fact used to work in the industry before he set his sights on mixed martial arts on a full-time basis.

4. He traces his martial roots to karate.

The son of an accomplished karateka, Krylov started training in kyokushin karate at the age of 10. He eventually earned his black belt and became a Master of Sports in the discipline and in hand-to-hand combat. Fans only need to look at his brutal head kick knockout of Ed Herman at UFC 201 to confirm his strong karate background.

5. He was the first Ukranian to sign with the UFC.

Krylov started his career in 2012 at an event in his home country. After his impressive showing in numerous promotions in Ukraine and Russia, he answered the call for his first Octagon apperance at UFC 164 opposite Soa Palelei. His most recent UFC appearance came in a defeat to Misha Cirkunov, as he left the promotion with a stellar record of 6-3. Other Ukrainians currently signed to the UFC are women’s strawweight Maryna Moroz and light heavyweight Alexey Oleynik.