The spell of peace prevents groups from warring by draining the will too fight out of them. It will not prevent individuals from fighting, but conflicts larger than bar fights and squabbles are pretty much unheard of. The line is vague and I'm afraid I cannot give a nice rule for drawing it; individual guides will have to decide what constitutes 'war'. Note that it only prevents violence, large groups of people may still disagree, rebel, etc., but tensions will never escalate beyond yelling.
Midnight Mere has tapped the magic powering this spell, allowing him to do magical feats above and beyond those that would be normally granted by priesthood. He does not fully realize where this power comes from, he believes that as Shimmer's highest priest, he has received special powers. The other priests of Shimmer are aware that he has these other powers, but they fully believe that they are just special gifts from Shimmer, even though the effects are not typical of her. Drawing on this power weakens the spell, but the relatively minor effects Mere normally performs are insufficient to cause any great damage except over long periods of time (longer than his natural life; it would take many generations of priests drawing on it pose a serious threat in this manner) Casting powerful magics with this power is another story.
This spell prevents Underlight from having any contact with other realms. It prevents both physical travel from neighboring realms, and magic travel such as gates. Those attempting physical intrusion get lost and misdirected until they give up. Those who would otherwise attempt to leave simply have no desire to do so. (Exceptions may be made for players to avoid violating the mind; but they will still encounter similar problems to those attempting to get in if they attempt to leave physically.) Magical measures (except for those on the same power level as the great spells, of course) simply fail; the gate closed when the spell was cast, and so on.
Priestess Summer Breeze has tapped the power of the spell of isolation, allowing her to do spectacular magic feats, as well as those out of the character of Shine's typical gifts. Late Frost has realized what is going on and warns her not to tamper with that power, but her thoughtless nature often causes her to ignore his advice, even though she respects it. Otherwise, the situation is very similar to Midnight Mere's.
Cast at the same time as the spell of peace, this spell reverses the night and the day from their former, natural positions, and perhaps a number of other aspects of the realm as well (the primary inspiration for this fact was the vast majority of fortune cards that came up reversed while I was designing the quest.) For the most part the realm has adjusted to the change, with but a few exceptions.
The sun roses and moon roses remain true to their original blooming times; the sun roses now bloom during the 'night', and the moon roses now bloom during the 'day'. Though it may seem a bit odd to the residents of the realm if they stop to think about it, the times before the casting of the great spells are mostly forgotten and the current patterns seem natural to them. The primary explanation for this goes something like this (told by a follower of Shine about Sun Roses.) "Their light is Shine's light. When the sun sets, the sun roses open so that we are never without it."
Also, outsiders (in other words, the heros) will find their 'internal clocks' confused; they will feel tired during they 'day' and ready to act during the 'night' (assuming they typically keep 'normal' sleeping schedules.)
Although the realm has mostly settled into a new balance, the reversal of day and night is still 'unnatural'. Additionally, the removal of the spell of reversal might change the realm's virtue and fault, and perhaps other things. Only extremely powerful magics can restore the balance. Unlike the other great spells, this one is not an enchantment which requires a power supply to maintain it; it was cast, had it's effect, and ended. The remaining power of one of the other spells might be a enough to restore one period.... (night to day or day to night, but not both at once)