After looking over Tatsurou's rejected worlds list, and his list of planned stories, this idea of mine was more or less ended. However, when I brought it up to Tatsurou, he said it looked interesting and suggested I post it HERE incase anyone wants to adopt it.

Sombra in Kingdom Hearts. At first, he is adopted (pre-BBS) by Vanitas, who feels some sort of kinship with him (Sombra being half Umbrum). Near the end of BBS, before the final Van/Ven battle, Vanitas would send young Sombra to a world where he would be safe (Destiny Islands). The story would then continue with Sombra winding up in a sibling relationship with Sora, who possesses strong feelings towards Sombra thanks to the influence of Vanitas within his heart.

6144117
That sounds pretty cool. Story concepts go here, though.

6144276
yeah, figured that out not even 5 minutes after posting this. I'm actually hoping that someone would adopt this.

6144286
If anyone does, please post a link to it here.

6144117
That sounds awesome, and I really hope someone writes this.