Then use Relaxing Smoke, to suppress the enemies' damage output entirely for a turn. It also has a low cooldown so you can spam it again and again. Use Peace Pipe first, to decrease your enemies' accuracy. Since he's an artifact, he can only be denied by CDA (which no monster in the epic have) and Stamina drain.
Tons of healing and stamina regen moves.However, monsters affected by it can still get a turn and inflict status effects or remove positive or negative statuses (much like Phantom/Space-Time immune only to damage except its a negative status effect), so his teammates can still be denied, debuffed, etc.
He can also inflict negative effects such as debuffs and a unique form of denial: Total Damage Reduction, which can prevent attackers from doing their job. He can support his teammates by healing them and filling their stamina full. Hippierion is an interesting support monster to say the least.