Thetis

Thetis is a kind boy that loves swimming and the sealife, but he wants to punish and rid people for dumping waste into the sea. He is the chosen one for model L, the Ice Mega Man. The player battles him at the Highway.

You encounter him at the arctic Ice Floe with Atlas. Instead of fighting you, he flees leaving you to fight Chronoforce.

You encounter him again at the Highway where he is attacking citizens to feed Model W. He megamerges and jumps into the ocean with you following him. HE explains that he is participating in the Game of Destiny to punish humas for polluting the sea. Then you battle him and defeat him. He retreats and takes the Model W with him. He appears briefly after you break Aeolus's cipher with all the other Megamen. He also appears after you defeat the 8 Psuedoroids in Ouroborous with Atlas, Aeolus, and Siarnaq. They are about to attack you when Vent/Aile arrive and fights them instead, allowing you to continue. After you defeat Albert, Ouroborous starts collapsing. Model Z seperates from Vent/Aile in order to keep Thetis and the other Megamen busy. Model Z freezes their Biometal which freezes them. Their fates are unknown but if you defeat the game in hard mode, you can see all the megamen well and alive in their megamerged forms.

Attacks
When you fight him, you're in the ocean, reminiscent of Leviathen's battlefield in the Zero Series. He dash-swims in the screen, attacks and then swim-dashes out of the screen. He sometimes uses the spinning halberd attack or the triangular ice projectile. If you're Grey, he'll use an ice drafon like Leviathin's. If you're Ashe, he'll create a chunk of ice and shatter it, causing the fragments to fly in differnt directions. He will also summon deep see monsters whitch create currents. Then he will create a shower of snowflakes, also like Leviathin's.