Some spells do Arcane damage. This heals imps and the arcane tower, and doesn't damage the caster. When a player uses either Shining Power or Lichdom, they can still use Arcane and Overlight or Underdark spells, respectively. Arcane spells/damage are not to be confused with arcane minions, which simply means the minions cannot be zombified.
A two way portal that can send one person, object, or minion through it per turn. Fire walls and lightning do not go through. For a minion to go through, it must be at least as small as an Arcanist. As soon as one object has gone through, the portal will appear empty. It becomes active again at the beginning of anyone's turn, whether they are the owner or not. If the spell "Hurricane" blows something though the portal, it will continue to get blown after entering the portal. However, "Hurricane" will not affect anything that is already at the other portal. Once the caster dies, the portal will disappear as well.
Any imps alive, including your opponents, will die and release arcane arrows, starting in an upwards direction (much like arcane bomb), and then moving to wards the pre-selected target. The number of arrows released by an imp is porportional to it's health, for example an imp with 78 health will release 7 arrows, an imp with 5 health will release 1 arrow, and an imp with 250 health would explode into 25 arrows. Because the most players is possible is 6, and the most imps a player can have is 4, and the most health an imp can have is 250, in theory, this spell can do up to 6000 damage, making it the spell with the most maximum damage. (Thorn bomb, with nature familiar, takes goes up to 6000, however it is literally impossible to take this much damage.)
Creates a triangle of three Arcane Glyphs at a selected location, which can be useful for blocking holes or portals. On rare occasions, you can sigil into someone and hit them in the same turn, although this is extremely hard.