u/KomodoLemon

Decided to give him more of a 60's - 70's paleoart design, make him look a bit more ancient, more monstrous.

Also required context:

By all accounts, Yarostni was nothing more than a Tarbosaurus that is slightly larger than usual. No attributes were placed upon him by the people of Nemegt that would make him anything more than a particularly large predator.  However, things changed with a series of killings in 367 A.E where Tarbosaurus killed a string of 22 humans in a single year. At the time, there were more humans killed by this individual than had been killed by the Tarbosaurus species all year. These were followed up by more killings by the same animal over the following years, and as it racked up bodies and scars, this Tarbosaurus became known as Yarostni the Hateful. Over the next decade, Yarostni would give itself new targets. In 371 A.E, Yarostni attacked Dozhd in the heart of Kuvshinka. This failed, as Dohzd’s soft underbelly is buried in the mud he rests in. In 373 A.E, it attempted an attack against Slepoy that resulted in the death of several Talons and a few new scars on Yarostni. He was eventually killed in 379 A.E by Chuánqí the Titan Feller after taking approximately 260 human lives. 

This is the story told by the people of Nemegt, however. There never was a single Tarbosaurus killing dozens, not originally. It was just a particularly bad year where Tarbosaurus attacks went up for a while, thanks to local hunting competing with their food supply. Stories spread that all this death could be placed on one animal, and the story of Yarostni was created. In response the people of Nemegt tried hunting Tarbosaurus, creating the vengeful Yarostni. A being so full of hate and pain it would never cease its violence.

Disclaimer: all names are placeholders