people try to make marik the stupid one and bakura the smart one but bakura tried to take over the world with a game of DND after 3000 years of planning and failed and marik was running a fully functional black market card mafia by 16 after living under a literal rock for 12 years so :
mariks the kid that somehow manages to run a full on homework crime ring and bakuras the kid trying to do it as the teachers walking around to check it