If you use Shadow Movement to sneak into houses and a pegasus team to pull the flying sleigh... yes, in this world, it's possible to become Santa Claus! But... the Christmas tradition doesn't even exist in this world. When Rimuru tries to explain it in detail to the people of Tempest, they end up summarizing it as a "party." The Christmas cake and presents are ready, and most importantly, Kaijin and the other Dwarves create gorgeous decorations that bring the Christmas mood to Tempest. On top of that, Eren and the children treat everyone in town with their heavenly singing.
I must ensure that everyone 
enjoys this Christmas!
!يجب أن أضمن أن يستمتع الجميع بهذا الكريسمس
Damit jeder seinen Spaß an Weihnachten hat!
Tengo que esforzarme
para que disfruten de la Navidad.
Tengo que esforzarme
para que todos disfruten de la Navidad.
Je dois aider à instaurer
une ambiance festive !
Devo esserlo, perché tutti possano godersi appieno il Natale!
Precisamos agitar, para que
todos aproveitem o Natal.
Я должна трудиться,
чтобы все насладились праздником!