Use stegos/shadowmanes to tank and deal some damage, maybe a yuty for the buff, the rest deinos.

What i used:

14 manes

5 deinos

1 yuty

Tatic:

Put a deino on passive, ignore group whistles, following yhr deino you're riding (min range), then, put everyone in the left side hill of the arena, so the fenrirs can't reach, them wait for the boss to come, and sendo everyone in the rush, them keep hit n running with your deino.

DO NOT FORGET THE BLESSED TEK CANTEEN ON WARM FILLED UP.

-Vinicius