the sniper Why do you think the sniper’s “lust of battle died in him?

I think this means that, now that his mission is complete, the sniper no longer feels the same about fighting.

Then the dying man on the roof crumpled up and fell forward. The body turned over and over in space and hit the ground with a dull thud. Then it lay still.

The sniper looked at his enemy falling and he shuddered. The lust of battle died in him. He became bitten by remorse.

Once the sniper saw his prey die, he no longer had a thurst to kill.