Newtype September issue has confirmation for the title of episode 23. (I’m not posting titles without source confirmation because I’ve seen people posting fake titles before. Better safe than sorry!) Previous episode titles post here with episodes 20-22.
23. Misfortunes never come singly.
-不幸は重なる・不幸は単独では来ない-
Meaning: Bad things tend to happen in groups. There’s no Japanese title available at the moment, but I’ll update it if I find it.
(All these titles feel so downers and full of suffering… Give us a break, please.)
This is Sternbild 
Oh, why so ominous, Nishida.
The titles for episodes 21-22 sound hopeful but then the title for episode 23 sounds terrible! Too much angst and suffering… Ahhhh ganbatte Kotetsu, Barnaby! ;A; ;;