LogFAQs > #979329927

His second strengthen quest is indeed not available yet. It was released with the 8th Anniversary - which for us would be July 2025.

His interlude though, should be. You probably haven't met the Bond requirement though. He needs to be at Bond Level 3 so just keep bringing him to battles and eventually he'll get there. If you've met all the other requirements the game will helpfully include the notice that the interlude is now available when he reaches that Bond Level.

While Strengthening/Rank Up Quests all (with maybe like one or two exceptions?) just require you to have the Servant at their final Ascension, Interludes typically have Bond Level requirements as well that you have to reach. It varies from Servant to Servant but with a single exception it will never require any higher than Bond Level 5 (and getting to 5 is generally the easy part, the bond requirements usually don't start getting much higher until after that.) There's also occasionally a story chapter requirement on Interludes as well - like for Hans you have to have cleared London which you've obviously done.