Yes there's one under the default Shinobi Arts skill tree. The Breath of Life: Light is a Latent skill allows you to recover a bit of HP from any successful Deathblows (including those landed one bosses). Try to get this skill as early as you can to conserve your Healing Gourd and Pellet use. Take note however that the amount of HP you recover from deathblows is not affected by the other medicinal potency latent skills.
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