Leech, of course, intended to claim the bodies of these Black Cavalry.
After all, these elite Black Cavalry were a priceless, ready-made asset. Although their bodies were heavily damaged—missing limbs were commonplace—the cost of repairing them with gold would be too high. But he didn't need to turn the corpses into simple zombies; having Ah Yamei summon and create Undead Knights from them would be sufficient.
After this battle, Leech would have a 50-strong force of Undead Cavalry under his command, men and horses included. While their combat effectiveness was greatly diminished compared to the actual Black Cavalry, they were low-cost and, more importantly, fearless in battle.
Leech gave the Necromancer Ah Yamei a mental command: after the battle was over and they retreated, she was to stay behind and turn the corpses into Undead Skeletons.
