@BugDevil:
That's 'cuz they're from a spinoff. Specifically the fourth spinoff, Yu-Gi-Oh Arc-V. Girl on the left is Yuzu, performer style of character, flash and flair, and in typical form for the series, does jack shit after the first arc despite being the closest thing to a female lead. Girl on the right is Masumi, extra-serious and deadly efficient, plays a burn deck (Gem-Knights). Masumi was introduced as a rival to Yuzu, playing up their connection and mutual respect after a rocky beginning. But when Yuzu became a kidnapping trinket, Masumi lost her relevance.
Super yuri subtext tho. Princess carry after a fall, there's a card named "Crystal Rose" that literally only works with their two decks (which Masumi gives Yuzu after making her promise to win a tournament in her stead), they even flashback to each other. Double tsundere never looked so good as a couple.