Chocobos can fight alongside in FFXV

ElRenmazuo

http://finalfantasy.wikia.com/wiki/Chocobo_%28Final_Fantasy_XV%29

Battles can start even while riding on a chocobo, but the party won't fight while mounted on them. If the chocobo does not want to fight it will run away. The chocobo's stamina depends on the things it is fed, good food allowing them to avoid enemies, while bad food may leave them with weak willpower and running into an enemy may have the chocobo run away leaving the party to fend for themselves.

Chocobos can be rented in gil for up to 30 days, and called at any time by a whistle. While riding chocobos, the players can press the jump button again to glide. When players dismount a chocobo, it will follow party for a while. The player cannot raise or breed chocobos. Chocobos can be taken to camp where they receive buffs. Dashing on a chocobo is said to feature a different music track.