notnik
Terrarian
It makes me feel a little sad to see that ninja just dissapear with king slime, so I thought up what seems to be a quick and easy happy ending for them. After defeating King Slime for the first time, He could emerge from the slime in tattered ninja clothing and work as a travelling merchant re-sprite, selling a variety of his items, and thanking the player before disappearing after 24 ingame hours. In order to make this a worthwhile addition, when a travelling merchant is going to spawn in, the game could run a chance (33% maybe?) for the ninja to spawn instead of the travelling merchant, wearing different attire and carrying a sword, mentioning that he has retired from the warrior lifestyle and now lives as a nomadic merchant. I'm not sure how hard this would be to add in as im not familiar with Terraria's code in any way, but this seems like a simple addition that would help build on to the world of Terraria.