Home»Game Guides»Persona 5 Royal Guide»Strength (Twins) Confidant Answers
You can make any dialog choices with Caroline and Justine, and you rank up the Strength confidant by talking to them in the Velvet room and fusing the required personas they ask for. You do not need a matching arcana persona when talking to Caroline and Justine, every request completed results in a rank-up. Completing the requests do not result in time spent, you can do them all in one-day if you want to.
The Strength confidant starts in May or so, and can be done almost anytime in the game except in the original endgame. In other words, try to do it before December because of plot reasons. The last required fusion is Seth, level 51, so once you reach level 51 you should complete the Strength arcana. Please click the video below to see my guide on completing all of the requests in one-go. All you need is the required level and some money to buy demons from the compendium to fuse the requests.