First of all, the reason why polymorphism appears is the change that must occur because of different times. At that time, the first single combat mode of Otto soldiers was not accepted by the public, or it could be said that it had caused everyone's visual fatigue. After all, there is nothing surprising or important to watch in a single combat mode. However, multimodal is different. Different forms have different combat modes, which can also give you different visual experiences. To this end, Altman must have a multi-modal combat setting!
Secondly, Altman's monsters are different, which means Altman used the same weapon at first. At the earliest time, every Altman fought monsters with his bare hands, but when they faced some monsters with weapons, they often lost, so it was for this reason that Altman began to change, and it was for this reason that Altman later appeared his own weapons. Then the shape of Altman can also be understood in this way, because the monsters that appear at present are more powerful than before, and the strength of many monsters is the same, so many shapes appear to better deal with monsters with different strengths!
Finally, the appearance of Altman may also be related to the improvement of ratings, mainly reflected in the appearance of Diga Altman at that time. As the first Otto warrior who appeared in various forms, his ratings after the release can be said to be very high. Even though Altman, who was once set in a single form, had high ratings, it was only the influence of the first generation of Altman who was released. And after more than 20 years of continuation, various forms have long been used to by everyone. So, to sum up, this is the reason why I think Altman is shaped!