Thank you all for the kind words, I really tried to take everything into account and it all fell into place surprisingly well.
@Eilrach that is an interesting idea, and not necessarily in contradiction in what I described here. One thing I did not mention is the possible reason behind Kapura always coughing up fireballs. In my ‘Many flavors of energy in the Matoran Universe’ topic, I mentioned that physical energy scales up with body size. However in some instances, certain beings can have more of it that their size would suggest, such as the Inika who were supercharged and were given special armor to contain the extra energy within their bodies. When part of the armor was removed such as the mask, the energy leaked out in form of light. It may be possible that Kapura also has unusually high amounts of internal energy which his body cannot hold, so the excess is released in the form of fireballs. It could be this extra energy that powers up the framerate altering ability. The energy builds up (or winds up as you suggest) and is released in a more focused and directed way than the usual fireball cough. Also, it wouldn’t be the first example of a character who constantly builds up energy, only to release it periodically (Kardas dragon). Vakama might have taught Kapura how to make better use of this energy.
@DuneToa that is something I thought about as well, but I later found out that there is one slight difference between Kapura’s ability and time manipulation. In movie 2 novelization, the usage of Vahi is described by Vakama as “slowing down his body and thoughts”, which means that Vakama’s own thought processes and perception of time were slowed down from his own perspective. This is slightly different from Kapura whose skill retains the normal self-perception of time on both sides. But yes, the two are similar and there is once again the Vakama connection.