You realize that they gave war elephants + that ability because Hannibal croosed the Alps with elephants. The devs just represented that side of history by giving this ability, and not "out of realism".
Besides, I just feel this thread is a bit of making a storm in a glass of water ... I'm not indonesian, and I don't know much of its history, nor about the symbol of the kris blade. All I know is that these kind of ondulated blades cause deep wounds extremely hard to heal, because that shape. Giving mysterious power ... I personnally don't think so. Anyway, with such logic, shouldn't the american minuteman be weaker than the regular musketman ? After all, minutemen were a militia, not trained soldiers. And the Mandekalu cavalry ? They shouldn't be any different from the knight. And so on ...