Harden Simms

Harden Simms is a good friend of Maggie and son of Lucas Simms. He is usually seen near Maggie in the mid-morning to late afternoon. He is very distant at first but will say a couple of words, but won't directly interact with the Vault 101 Dweller (unless his father is dead when you deactivate the Megaton bomb).

An interesting note, if you kill his father, Lucas Simms, and wear his clothing (Sheriff's Duster + Sheriff's Hat) he may say, "You might wear his badge but you're not my dad" whenever you pass him in Megaton. If his dad is nearby he will say "Hey mister, you better not try anything, my dad is over there." After that you can talk to him with dialogue options.

You cannot kill Harden Simms directly with gunfire, but he presumably dies if you choose to blow up Megaton.