After generations of refinement and the obsession of the deadly hidden weapon of snakes, The Hidden monastery of the Serpent Succour has finally mastered the way of initiating Monks and Monk initiates to using the ritual of Zehir after years of slowly bolstering immunities with locally collected venoms and poisons both extracted raw and refined in potency. When the ritual is completed the participant is forever changed, the skin grows paler and blackened veins surface. The deadly weapon of snakes is now a core function of a Monk of the Serpent Succour's very life source.

Venomous Blood

Starting when you choose this monastic tradition at 3rd level, your very blood has been infused with deadly venom. You have resistance to poison damage and are immune to being poisoned. You count as always being poisoned, but suffer none of the effects of the condition. This condition can only be removed by a wish, divine intervention, or another equally powerful force. If you are ever cured of this poisoned condition, you lose all features of this monastic tradition.
     In addition, you can use your bonus action on your turn to perform a bloodletting and suffer 1 slashing damage that cannot be reduced or prevented. Until the beginning of your next turn, whenever you deal damage to a creature with an unarmed strike or melee weapon attack, that creature must make a Constitution saving throw against your Ki save DC. On a failed saving throw, they are poisoned until the end of their next turn.

Blighting Breath

Beginning at 6th level, you learn to focus your breathing to expel venom or sniff out the presence of it. As an action on your turn, you can expend 2 ki points to cast detect poison and disease or stinking cloud.

In addition you learn the poison spray cantrip. Immediately after you cast poison spray on your turn, you can expend 1 ki point to make a melee weapon attack or unarmed strike as a bonus action. Wisdom is your casting ability for these spells. When you cast these spells, they require no components.

Sanguine Miasma

Beginning at 11th level, your accursed blood is capable of making the air about you toxic when you are badly injured. When your hit point total is below half of your maximum hit points (rounded down), you are surrounded by a blood mist that causes creatures within 10 feet of you to have disadvantage on Strength and Constitution ability checks and saving throws. Creatures that are immune to being poisoned are unaffected by this feature.

In addition you no longer need to suffer damage to use the bloodletting portion of your Venomous Blood feature while below half of your maximum hit points (rounded down).

Aspect of Zehir

At 17th level, you have learned to become one with the contamination within you for short periods of time. You can use your action to enter a trance-like state, gaining the following benefits for 1 minute:
•   You are immune to poison damage.
•   Creatures you have poisoned are vulnerable to poison damage you deal.
•   You do not need to be below half of your maximum hit points to benefit from your Sanguine Miasma feature.
•   You can cast the contagion spell once without requiring components. Wisdom is your casting ability for this spell.

This state ends early if you are knocked unconscious, reduced to 0 hit points, or die. You can also choose to end the trance on your turn (no action required). Once you use this feature you cannot do so again until you complete a long rest.