For context, Hector is considered one of the best units in the game, and a high-leveled Hector can tank whole stages, even moreso than most overleveled units. (Especially with a healer like Serra hiding behind him.) If you have a unit you want to power-grind, having a unit that can beast the game solo while the grinding target just darts out to hit the things they have weapons triangle advantage over is one of the faster ways to go about it.