Durarara!!x2 Ten Episode 12

"It Takes a Thief to Catch a Thief" is the twelfth and final episode of Durarara!!x2 Ten and the fifty-second episode overall of the Durarara!! anime.

Synopsis
Mikado Ryuugamine continues his purge of the Dollars in an attempt to realize his ideals. This escalates into a clash with the Yellow Scarves. Izaya goes after Yodogiri, the man who stabbed him, but there’s something unexpected behind it all that even Izaya couldn’t have foreseen. What lies beyond the numerous uproars cropping up all over Ikebukuro? Various incidents intersect, and the story plunges ever deeper into further chaos!

Adapted From
adapted from what manga or LN chapter?

Referbacks
references to previous episodes?

New Characters
In order of appearance (not including OP)

Characters
In order of appearance (not including OP)
 * 1) Celty Sturluson
 * 2) Emilia Kihitani
 * 3) Egor

Unanswered Questions

 * Why is everyone at Celty's apartment?