What If? Doom Slayer appear in Attack on Titan World ?

[Marnuplee]

after defeating icon of sins, ROB transported Doom Slayer to Trost District when battles against titan were raging and Eren carrying huge boulder and trying to seal the broken gate. Slayer decide to help humanity fighting against titans.
how would the rest of people of attack on titan react to Doom Slayer ? how the story changes with the slayers intervention ?

 

[CarlManvers2019]

Eventually he reaches Marley and beats up the Marleyan High Command and the Tybur Family

Along the way, he somehow travels back in time to beat the shit out of King Fritz whose screaming for help