Dragon: REEEE
Klaus: Wait, you got the wrong guy, I'm just a mob with a stick, want me to remind you who's actually responsible for bringing that Hero Sword stuck in your bum right now?
Dragon: ...go on.
Watch the guild have no response regarding the rarity/power of his cards because they're so strong they fry/corrupt the equipment/servers. The guild onee-san will want to charge him for the damage but can't because it's top-secret/too anomalous to explain.
Using lightning magic on the brain to alter memories...reminds me of the MC doing that in another series Tsuihou Bokensha no Yarinaoshi ~Yousei-kai de Kitae Naoshite Jibun no Ibasho wo Tsukuru~ Outcast Adventurer's Second Chance ~Training in the Fairy World to Forge a Place to Belong~
That...