I just read a question about time travel in anima and I'm wondering there. I've the core rules book from the beginning of the anima-rpg and at least in there I don't remember reading anything about that. So my question is: Is there any book where time travel in anima has been introduced and if so which one?
Time travel as per the classic definition (physically moving oneself to a different time) is not mentioned, at least not to the past. If you analize the several means that exists for traveling time or altering past events, you'll realize a trend: They are severely limited in one or more ways.
In the core book, we have the Eye of time spell, that allows you to send your senses to the past and observe the events that transpired. Note that this is he wording from the second edition of the core rules , first edition description is much more ambiguous, categorizing it as a "limited time travel" that allows you to witness past events, but it was not clear about the limit of you interactions with those events.
The spell Uncreate allow to erase things from existence, but it is limited in that it so it can only be used on things that exists in the present, and past events involving the uncreated objects or being are not affected, they merely happened in another way that did not required the uncreated entities.
In Arcana exxet you can find the time path of magic, that allow manipulation of time, but most of the spells only works on limited areas or specific targets. It can slow or stop time, or make things or people older or younger, etc. Among the higher level spells you can find effective time travelling (but only to the future), time rewind(but only in a a small zone and only small amounts of time),time loops (but only in a limited area) and even the ability to overlap past and present, but the spell is unable to effectively alter the past.
The important part, however, is at the end of the time path spell list: A small note informs that the Powers in Shadow continually surveys te use of magic that mess with time, and that any spell that could end in an alteration of the past is left without effect. Is possible that they are trying to prevent any disaster, or maybe there is something in the past that they want to remain forgotten, but the case is that there is no aparent means for time traveling because there is certain parties very interested in making that impossible.
Of course, that the temporal blockade is really impassable or not is in the hands of the DM, and would not be the first time that the Imperium systems fails them...