It's unclear if this is lampshading, or just YGO being YGO.
not to mention Fubuki's heartbroken reaction to Ryo being Not Brainwashed (just broken) in Season 2. Ryo and Fubuki certainly seemed close before Fubuki disappeared.Edo is also the only character who seems to be on a First-Name Basis with Ryo (Sho uses "onii-san", everyone else calls him Kaiser), and obviously worries about Ryo's deteriorating condition ( not that Edo would ever admit he cares). The endless sass doesn't do anything to defuse the subtext, either. Edo and Ryo live together for part of season 3, and they sure seem to have that "master and servant" act well-practiced.Sure, Manjoume is a fanboy of both Tenjoin siblings, but the way he idolizes Fubuki with Manjoume calling Fubuki onii-san, and when Manjome does he sees sparkles around Fubuki, makes them looks like genderflipped version of typical onee-sama relationship in yuri mangas.Let's not forget Saiou/Edo Phoenix, or the newly opened Fubuki/Yusuke Fujihara (from season 4).In season 3, Ryo's awe-inspiring final duel with Yubel snaps Judai out of his Heroic BSoD after three other Heroic Sacrifices have failed. Dub Text adds Jaden's incredulous reaction to Syrus claiming that he "got the looks". Judai blushes during his first duel with Ryo, and remains extremely impressed with him for the remainder of the season.Speaking of Yubel, their ever-ambiguous gender even extends to their past life as a human.In Breaking the Sacred Seal, Syrus (still a duel ghoul) ran up to Jaden and hugged him while demanding him to duel him.
In Episode 64, Camaraderie Contest, there is a light scene of Jaden calling out to Syrus while running over to him and Syrus happily runs over to Jaden.Then Jaden says to Syrus that he's still looking after him and that he still has his back, then he asks Syrus if he'd do the same for him, making him blush and Syrus replies that he does. In Episode 137, Syrus had a dream of him and Jaden talking.At the end of Get Yarr Game On, Syrus says to Jaden while swimming to his rescue that he wants him to be his "shipmate.".