worldsworstgrandpa
According to Nintendo Waluigi isn't related to Wario

He’s just some guy who randomly showed up one day that became friends with Wario. That makes it even better. Nobody knows where Waluigi came from. He just exists.

yardovich

whats even better is that Waluigi’s first appearance was in Mario Tennis, meaning that the only reason he showed up in the first place was because he wanted to play tennis with people. nobody had ever heard of him before and he just shows up to play tennis

captainsnoop

That’s why Waluigi is never in any of the main games. He only knows Wario and he only wants to play sports. He’s just some guy that met Wario at the tennis court and he hangs with Wario whenever Wario goes out to play sports, and otherwise he minds his own business.

Waluigi probably has his own circle of friends that we’ve never seen. There’s an entire world of Waluigi that we haven’t touched upon simply because he isn’t the adventuring type. Wario phones him up and says “Hey bro, I’m-a gonna go on an adventure to get-a some jewels from a pyramid. You wanna come with?” and Waluigi’s just like “Nah bro, I’m good. Me and my buds are gonna swing by the coffee shop and go to the library today. Hit me up if you wanna go go-karting though!” 

God damn. The mild world of Waluigi. 

the-eagle-atarian

The lore deepens

a-random-mod

Waluigi is the best.

jestre

Did seriously no one ask for a source to this? Source, please?

a-random-mod

Well, it was charles martinet, the voice of most mario character including waluigi, who said they weren’t related. Well, him and the official mario party 5 guide.

jestre

You forgot to link that for sake of verification. :P

silver-tongues-blog

It’s hard to link a specific page from a book and the only things I have to verify it are a broken link and multiple wiki articles that state the same. But I know you don’t believe wiki articles.