Gold Coin
Blue Coin
Coin is the in game currency. It is automatically awarded by killing enemies. Scoring combos with give you bonus coin. The more kills chained together and the more creative the kills, the higher the reward. See Combo (OMD3) for more information.
The amount of coin awarded differs by the type of enemy, generally the harder they are to kill the more they are worth.
Dropped Coin[]
Many enemies have a percent chance to drop coin when killed. These must be collected before they can be spent on traps. Small gold coin typically are worth 20 coin and large gold coin are worth 50. Small Blue coins are worth 100 and large blue coin are worth 250 (typically dropped by mini-bosses). Mr. Moneybags always drops 500 coin when killed.
Lore[]
Also known as "Arcane Coin", "Rift Coin", and "Rune Coin".
A theory surrounded having to spend coin on traps to defend the rift is that the Order purposefully opened the rifts to allow enemies through in order to create a reason for traps to exist. The Enemies have been paid by the Order to invade and the Order overcharges for its trap rental assuming you the player are able to overcome the enemy.