Eregion

Eregon (イレギオン) is the boss of the Intro Stage in Mega Man X4. In the first half (Sky Lagoon), the player must outrun him to avoid its claws and shots, and must also destroy the locked doors to get away.

In the second part (the city ruins), the player must fight. X should use charge shots, and Zero should keep wailing on him with his Z-Saber. Just watch for his body attacks (when he flies), his claw swipes, and his laser "breath". After the defeat of Eregon, the player will encounter Colonel for the first time and learn of Repliforce's declaring war for independence.