The main antagonist of the story, Makoto has a strong sense of justice and a tendency to protect the weak and outcast in disregard for his own safety (especially if it's a girl). Upon seeing Mana fight an alien he instinctively tried to protect her, as dangerous (and suicidal) as the situation was.
Makoto is from the Tobita Clan, known for their spiritual powers and monster exterminating skills. Makoto lacks any fighting skills but can still be used as a power booster for Mana. If swallowed by Mana he can give her a tremendous boost to her power, but at the cost of his own life if he is not careful.