Thanks dude, I've always wanted to be called a geius! :p
I took care of Mecha Sion, RiotSoundBear took care of the other two. I for sure can't tell you exactly how it was done, since it took about 50 pages to walk regional VO teams how to do it (lots of pictures) and Soraka and Lissandra were around 40.
So here's sorta how we did it; this might be confusing -
High level - both VOs make really good use of feedback to get the crazy sounds. The main Mecha sound is different types of short delays feedbacking into themself. Soraka and Lissandra are more of a pitch feedback sound.
Mid level - Changing delay times between about 20 milliseconds and 40 milliseconds over the course of a VO line can change the pitch of a line. Feedbacking these delays makes them take on a metallic tone. Lots of robo voices use this technique. Faster delays = high pitch. Your ear won't hear delays below 50ms seconds as delays, it hears them as a part of the sound it came from, so we like to use that quite often.
Low level - So many audio plugins. Pitch, delays + feedback, subbass, reverb, different types of modualtion to make the sound move, EQ
And we don't just throw this processing on one single Vocal track. We make a bunch of copies of the VO lines, then do separate processing to get a layer of the sound we want, then mix it all together to make it sound like a single person speaking.
If this made sense and you want me to elaborate let me know!
Cheers.