Closing the poll for Part 3. With this one ending in another tie, I've decided to go with the original Plan B: Combining both monster slots. Therefore, the list of upcoming opponents will be:
21. Aku (Samurai Jack)
22. Arctic Giant (Superman 1942)
23. Trigon (Teen Titans)
24. Koopzilla (Super Mario Bros. Super Show)
25. TBA - Special 25th pic pick
Will probably open a poll for the 26th opponent towards the end of my subscription, or for something MMD-related. Stay tuned!