One of the strangest video game crossovers of all time happened on the Nintendo 3DS, as Sephiroth from multiplatform nature of Monster Hunter Rise seems like it will prevent any first-party collaborations on the Switch.
Monster Hunter 4 Ultimate on the Nintendo 3DS had armor and weapons from series like The Legend of Zelda, Metroid, Super Mario Bros., and Animal Crossing. There were also third-party crossovers, as well as ones from developer Capcom, including Sonic the Hedgehog, Mega Man, Devil May Cry, and Street Fighter II. The fact that Monster Hunter World was a multiplatform game meant that its crossovers came from Capcom or third-party developers, as well as with the Monster Hunter movie.
One of the crossovers that happened during the Monster Hunter 4 Ultimate era involved Tetsuya Nomura, who designed armor and weapons for the game. Nomura is an iconic figure in the video game industry, known for his work on the Final Fantasy and Kingdom Hearts series. Nomura worked as the co-director on FF7 Remake, but he is stepping down for the sequel. The items created by Nomura for Monster Hunter 4 Ultimate can be seen on the Monster Hunter Wiki and one of them should look familiar.
FF7 & Monster Hunter: One-Winged Judgment
Nomura designed a Long Sword called the Wing of Judgment, which is based on Sephiroth from FF7. Sephiroth can be seen embedded in the hilt of the blade. The blade itself is meant to look like a single black wing, referencing Sephiroth's appearance during the last battle of FF7, as well as his "One-Winged Angel" theme from the same fight. Nomura also designed the Rage Armor (seen above), which is based on Diabolos from FF8, as well as the Purrity Palico Armor, which is based on the Warrior of Light's armor from the cover of FF1.
This wouldn't be the last time that the Final Fantasy and Monster Hunter series would cross over, without even counting Cloud, Sephiroth, and Rathalos appearing in Super Smash Bros. Ultimate. Rathalos would appear as a boss in FF14, while a Behemoth appeared in Monster Hunter World. The two series are very compatible when it comes to crossovers, outside of sticking one of the most iconic faces in video games in history onto the handle of a Monster Hunter sword.
Image Source: Monster Hunter Wiki