Summoners War: Chronicles

Best Dps - Argen, Narin Ha, Tesa
Best Supports - ShuShu, Bastet, Verdehile, Fermion, Bernard/Remy
Fire Phase - Make sure at least one uses Verdehile for the crit res down as boss has 80% crit res up, to break altar requires two attacks from when you see a crosshair on you or your allies.
Water Phase - Weakest Phase, red shield = dont hit boss otherwise will receive reflected damage.
blue shield = hit boss to break Bring boss close to fire altar, when puddles come place puddles on the side of altar to make it possible for two people to place at once easily and to make it less awkward when you need to place another while the current ones are still there.
Wind Phase - Have one designated person on tower as when lightning comes down to break the altars it can be messy if more than one person tries to do it. Stay away from each other and avoid letting the lightning hit the other altars as it'll cause AOE damage to you and others.
After 3 Phases go to designated areas to each kill the Tesa, Undine, & Slyph. Once finished with yours you can portal in to your allies and help them if needed. Strips or dps the undine fast when it revives to avoid her reviving constantly.
Final Phase - Has the red & shield phase occasionally to be attentive to not accidentally hit it when red shield is up as it'll reflect damage and gain extra health. try to dodge all abilities and not lose units. Heal block is very nice here.