My Idea of what Devil May Cry 6 should/could be about. now just to be clear i have only played the games (all 5 + reboot) and season 1 of the netflix anime but i dont think that last one really counts towards the lore. so if anything i say here explicitly goes against a magna tie in from like 2008 or something then feel free to correct.
I'll go plot then gameplay.
Mundus has been stuck in hell healing himself since the end of DMC1. Mallet Island was the only place on earth he could escape from before. now the island is gone and he belives he is stuck forever. He has discovered that a way to become free is if he uses the blood of the one who sealed him away initially to create a portal in witch he can escape from. He can send some demons through but he cant get through himself without the seal being broken. however, sparda is dead and dante,vergil and neros blood wont work because after a certian point the blood of demon and human mixes and it become (impure). Kyrie however is pregnant with her and nero's child. so mundus sends his horde to retrive kyrie and the baby. nero fights them off and leaves lady and trish to protect kyrie while he ventures into the underworld to fight mundus. it dosent work and nero is defeated. he is saved however by dante and vergil who team up to help him defeat mundus. for that to work tho, nero needs a stronger sword and a form of sin devil trigger like the sons of sparda. so while nero heals dante and vergil travel to the ruins of mallet island to retrive alastor so nero can fuse it with the red queen. nero transforms the red queen ( devil sword credo, the black king idk pick something) and the 3 head off to fight mundus. dante is eager to end mundus and vergil for the first time ever shows fear in the idea of fighting someone (not quivering in his boots or anything but hes notably not at ease)to mess with nero even more, much like how mundus made trish to look like ava, mundus created another demon that looks like credo. eventually the 3 defeat mundus for good dante and vergil return to the human world but venture off to parts unknown and neros child is born.
Now for gameplay or like structure of gameplay. the game would have 20-25 missions. for the sake of this lets go 25. you play as nero for the first 10, once you get to mundus and loose, you then switch to dante and vergil while nero heals for missions 11-20, dante and vergil where like for some missions in dmc 5 you can pick between dante or vergil. once nero is healed up he then gets his new sword and sin form, you regain control of him for 22-25 or for 22-25 you can choose between any of the 3. mission 21 being the mission you get the new sword and stuff and defeat the cerdo look-a-like demon.
once you beat the game you then unlock LADYS NIGHT mode. you play as lady and trish protecting kyrie for 10 missions (or so, you just replay the first mission maps of nero in the human world). the final boss of this mode can be the cerdo look a like. you can throw nico in there too and give her V's gameplay but with robots or something. the way ladys night works is that you can choose between the 2 or 3 girls every missons so you can play half lady half trish or all lady or all trish.
anyway yeah thats my pitch.
