Board Thread:Questions and Answers/@comment-1031724-20161029080114/@comment-1031724-20161110031343

Recurring minor villains die in their second appearance unless they reform. Recurring main villains survive to the end: Loki, Thanos, and Zemo (Zemo won't live forever coz he's mortal, but he'll live for the duration of the series), and I've already made me Phase 3 point - if the villains of Guardians 2, Spiderman Homecoming, Thor Ragnarok, and Black Panther survive, I'll say Kaecilius is still alive as well, and further proof that Thanos survives

Besides, isn't this what you want? A villain sticking around for the duration of the series instead of being a "lame, disposable one-shot" like Obi, Vanko, Red Skull, Killian, Malekith, Pierce, Ronan, Ultron, Cross, and possibly Kaecilius?