RTF is a global modification that replaces all towns in the game.

Comrades... the developers themselves called Snow Ape Yeti... someone found a text description, and there's also the ability "Agility," which is specifically the Yeti's ability, but for some unknown reason, this creature was banned... according to an insider, the people at Ubi rejected this creature, saying that wolves are okay, but Yetis are not...
Heroes of Might and Magic V - Tribes of the East\data\texts.pak\Text\Game\Creatures\Neutrals\SnowApe\
Name... Yeti
Abilities... Endless Retaliation. Agility.
Description... Yetis possess extraordinary abilities. They respond to all attacks made by the enemy and are also capable of preparing for battle while moving towards their opponent, increasing their "Defense" parameters. The longer the Yeti walks towards the enemy, the better prepared it will be for the fight.

Heroes of Might and Magic V - Tribes of the East\data\data.pak\GameMechanics\Creature\Creatures\Neutrals\SnowApe.xdb