Mothkin are a species focused around a unique spellcasting gimmick that differs from those already present in the game. They have a chance to cast an inscribed spell without consuming MP whenever they attack or manually cast a spell. This chance rises experience level and decreases with the level of the spell being cast and its failure chance. Spells can be cast this way even when under the effects of silence and never miscast. This chance is only checked once per action.
In crawl, hybrid casters are not favored because of their poor action economy. You can only take one action each turn, so builds that have one very good way of killing things function better than builds that divert their attention between magic and melee. Why bother casting fireballs if you can already swing an axe well and doing so would make you weaker? This species is intended to offer a new way of building characters by letting you do both simultaneously.
They have a unique second trait that supports the automatic use of spells in melee by making them immune to damage from their own spells.
The price they pay for this power is reduced mp capacity and manual casting speed. This hampers their ability to rely on manual spellcasts and forces them to make use of their unique spellcasting gimmick if they wish to cast a lot of spells.
They have mostly-balanced aptitudes and stats to support a hybrid playstyle. They have poor aptitudes with stealth and shields. Their positive evocations aptitude encourages the use of orbs over shields in the off-hand. Having previously undergone metamorphosis, they are good shapeshifters.
See the pr here: https://github.com/crawl/crawl/pull/4751
This species is now available for playtesting as an experimental on CDI. To play, register and log in at https://crawl.dcss.io/ and click Mothkin under Experimentals. You can also play on console via SSH on port 22 with user crawl and using the CAO key. The RC file used is that of your trunk RC, so use the trunk edit rc link to change your settings. All games played on the experimental won’t be scored on either CAO or Sequell.