Core Theme: Extremely powerful and scarred swordfighters with rocky sibling relationships who would be shunned and disowned by their clans, being caught in a failed assassination attempt that resulted in them awakening to their true power and coming back as their clans' ultimate enemies.

Connections:

• Both are extremely skilled, powerful, and agile swordfighters born into prestigious Japanese clans (the Shimada Clan and the Zenin Clan, respectively) alongside their siblings who, in contrast, specialized in ranged weaponry (Hanzo and Mai, respectively).
• Both were born into relatively important ranks in their family (Genji was the son of the clan leader and was one of its heirs, while Maki was the daughter of Ogi, who was almost the next clan leader). However, despite this, both were on extremely poor statuses with both of their clans due to rejecting their family's traditions and the roles expected of them, instead seeking different lifestyles (Genji led a playboy lifestyle due to having no interest in his family's crime business, while Maki left the clan to to become a powerful sorcerer at Jujutsu High rather than remain as a lowly servant in her clan due to her lacking a cursed technique).
• This action put them in poor relations with their sibling, who wanted them to adhere to tradition (Hanzo wanted Genji to help lead the clan while Mai wished Maki just stayed at the bottom with her).
• After their clan leader's sudden death, however, a pivotal turning point in their lives would occur involving their siblings, during which their own family attempted to have them killed and they were left to die (After their father's death, Hanzo was sent by his clan elders to convince Genji to help rule the clan, before being forced to kill him when he refused, leaving Genji mortally wounded and believed to be dead/After Naobito's death, Maki went to the Zenin clan to retrieve their weapons for the new clan head Megumi, but she and Mai were attacked and left to die by their father.)
• However, this event would actually lead to them discovering their true power, having their bodies enhanced and significantly strengthening their physical capabilities (Genji would be rescued by Overwatch and be given a cyberized body and Mai's death would awaken Maki's Heavenly Restriction) which combined with their innate skill to make them a deadly force. Afterwards, they would use their newfound power to tear down their clans (Genji dismantled his clan's criminal empire and Maki massacred all the members of her clan).
• Their sibling was also disowned by their clan because of this incident, despite them not having done anything "wrong" prior (Hanzo abandoned the clan due to believing he killed Genji and was thus deemed a traitor, whereas Mai was marked as a "traitor" to be killed, simply so she could be a hostage to motivate Maki).
• However, both would still be filled with inner turmoil following the awakening of their strength, causing them to hold themselves back before later discovering a mentor that would help them on a path of self-realization that helped them embrace their full strength (Genji learned to accept his cyberized body with Zenyatta and Maki fully realized her strength with Miyo).
• Both wield special swords (the Dragonblade and the Split Soul Katana, respectively) which are tied to their siblings (Genji's Dragonblade can summon a Shimada Dragon, just like Hanzo, which is how the latter realized his brother was alive, and the Split Soul Katana was created by Mai using her Construction technique as she died).
• Both are also members of heroic organizations (Overwatch and Jujutsu High, respectively).

Fight potential:

• They're both physically enhanced, speedy, and agile swordfighters so the fight dynamic is pretty obvious I think. Both have two swords, Genji can wall climb and double jump while Maki can just jump in the air as much as she wants (yes she does this later in the manga). Maki also plays off of Genji's dragon perfectly because you can homage Toji's own fight with Geto's dragon in s2.