black luster soldier card sleeves Sleeve 200 Pack Compatible with Yu-gi-oh Card Sleeve Japanese Small Card 62x89mm, Back Textured Perfect Shuffling, Protect Your Japanese Sized Trading Cards Photocard Never Tear : Toys & Your opponent cannot activate cards or effects during your Battle Phase YGO - Card Sleeves -

Outside of their different third colors, they also do different things

In addition to looking similar, both are delinquents (with Joe being a confirmed orphan while Valon is implied to be one) who ended up going to prison before being taken in by an evil organization to be used as a major asset (thought Valon ends up sticking with the organization while Joe defects and fights against them)

Omnath is a Constructed and Cube staple thats incredibly powerful in any format with fetch lands

Additionally, I think it is a very flavorful card, as the two life it costs to cast beautifully illustrate the characteristics of the black color in Magic: The Gathering