Crimson charm

Crimson charms are used in Summoning to summon certain creatures. The amount of experience gained from each charm used varies between 83.2 and 1015.2 depending on the pouch made, making crimson charms the second most powerful charm after blue charms. Crimson beats out blue in one aspect — creating a Talon beast pouch using a Crimson charm gives 1015.2 experience, the highest of any pouch. However, Talon beast charms, which are required for the pouch, can be time consuming to obtain.

Two crimson charms and 150 brilliant energy can be transmuted into one blue charm with level 84 Divination.

Familiars
The following familiars require a Crimson charm to make their pouch:

Monsters that drop crimson charms
Monsters with a significant crimson charm drop rate (greater than 10%) are listed below. It is not meant to be inclusive of all monsters that drop crimson charms.

Other sources
Thieving
 * Dorgesh-Kaan Average Chest
 * Dorgesh-Kaan Rich Chest
 * Amlodd worker

Other Methods
 * Charm sprite hunting
 * Soul Wars rewards
 * Spirit implings (tradeable spirit impling jars do not have any chance of giving charms.)
 * Freeing a Fire Spirit

Weinrotes Siegel Crimson charm Crimson charm