Many of us older players fondly remember Cecil from the 16 bit days. A dark knight who turned into a paladin of light.
Just like in ff4’s story he probably would not do well on his own against dark units, especially Kain. But Cecil is a team player, who sacrifices some of his own hp to protect the rest. This resembles the cover/protect skill in ff4 where Cecil, once he becomes a paladin, keeps jumping in front of teammates to protect them from a fatal blow.
Still Cecil is not quite a complete tank like WoL or Engelbert, but rather a tank supporter. He has no skills to increase hate, but he can buff himself and the rest of his team quite well, and has a good atk stat.