3. Krang
An enemy that could have potentially already made their debut, Krang would be another good choice for the sequel. Maya Rudolph’s character Cynthia Utrom may have already given us the debut of Krang in secret.
While the character may seem different to Krang, she has many connections to the classic character. From the appearance to her last name being very on the nose (Utrom being the name of Krang’s species), it seems almost certain that Cynthia is not all that she seems.
Revealing the character to be a robot body operated by the Utrom Krang would be a great move for the franchise. It would open the doors for this franchise to explore the extraterritorial sides of the TMNT universe, including alien races such as the Utroms and Triceratons.
2. Slash
Another classic character that would make a fun addition to the sequel would be Slash. Cynthia Utrom was close to extracting the DNA from the TMNT, with TCRI managing to “milk” some of the turtles’ blood. What if this DNA is used to create a fifth turtle?
This could lead to the creation of the villainous Slash, who could be used as TCRI’s answer to help defeat the TMNT. Slash has had a number of depictions, however, it would be interesting to see the sequel tackle a hulking version of a character similar to the IDW Comics and 2012 series.
The 2012 series saw this hulking version of Slash demolish the Turtles in combat, and only narrowly being defeated by Raphael. This character was terrifying and posed a serious threat to the team.