I couldn't finish 'em. Looks like this's gonna get complicated.
Manatoise can be tough if the party doesn't heal effectively as its Carapace attack will do 30 to 40 damage to well-equipped party members. Its Fire often targets the whole party for 20-30 damage while Thunder is used more for attacking one member for 30-40 damage. It is weak to Ice.
The fastest way to beat the Manatoise is to have everyone in the party defend while Elgo casts Blizzara. While Manatoise may use the Carapace attack, which initially deals a lot of damage, defending party members are almost guaranteed to survive assuming Manatoise doesn't constantly target one member. With Auto Battle on, using this strategy can kill Manatoise in approximately 30 seconds.
Its name is a portmanteau of "mana" and "tortoise". Mana is an indigenous Pacific Islander concept of an impersonal force (false ego) or quality that resides in people, animals, and inanimate objects.