Unlocking the infinite Devil Trigger in Devil May Cry 5 does not require you to find a specific weapon or visit a certain location. Instead, you will have to do multiple playthroughs on different difficulty levels with the Super Costumes for V, Dante, and Nero unlocked.
Devil May Cry 5 Infinite Devil Trigger
This Devil Trigger allows you to use your character’s powers and do transformations. It is marked by a purple bar under your health and this gauge increases by 1 with a Purple Orb.
The first thing that you need to do beat the game on “Human” or “Devil Hunter” difficulty. Finishing any of these two difficulties unlocks the “Son of Sparda” difficulty level.
Once done, beat the game on “Son of Sparda” difficulty. This unlocks the “Dante Must Die” difficulty level.
Finally, complete the game on “Dante Must Die” difficulty.
This will unlock the Super Costumes for each character. The playthrough will be extremely difficult, therefore, be sure to farm a lot of Red Orbs to max out your weapons and skill. The suits unlocked will be Super Nero, Super V, and Super Dante.
Select the Super Costumes before you start a mission in order to gain the ability to use this Devil Trigger. This will really help you when you play the game on “Heaven or Hell” difficulty.
However, this comes at a cost as your rank has a penalty of 80% that makes getting an S-Rank almost impossible.