If you're referring to the Fandom wiki, that's an interesting topic of much debate, and I have nothing to do with it. It's got 1 or 2 main editors, but the real contention is the wiki attempts to link everything between every game plus the anime as a single cohesive piece of information, which ends up causing a lot of made up fan fiction just to connect the dots. The source material has been argued to be legitimate, but when pressed for the source, the wiki authors admitted that the data was from a Japanese cooking blog... which is never named, and no longer exists and cannot be found on any internet archive to cross reference
Additionally, the fandom wiki contains many completely made up monster lores and flavor texts from the Japanese translations that don't correlate. I did make an attempt to explain to the editors, using 1 particular monster as an example comparing the English text to the Japanese text. I provided the real translation and the likely meaning behind the name and lore description based on the direct translation of the name itself and the flavor text. This singular entry was changed, but none of the other hundreds (maybe thousands) of entries have been touched. Much of the guide information on the Fandom wiki is also out of date, or based on pre-data mining posts from the 90s/00s and not updated to the current findings that engineers and code hackers have discovered and published. If there's one thing the Fandom wiki has going for it, is that it has an impressive number of images across the many genres and platforms Monster Rancher has appeared on. I just wouldn't recommend trusting it for actual game information.
LegendCup isn't trying to connect everything to everything just for the sake of it, and doesn't acknowledge the Anime as a source of cannon for the games. Sort of like if you were to purchase a game guide about something, Each game's FAQs and guides are researched and dissected in isolation mechanically, and doesn't attempt to be a guide to the lore and history of monster rancher outside of providing references of actual in-game flavor texts of monsters within their respective games, along with data mined mechanics and information within each game.