Poisonous fangs, webs of lies, in other words a perfect agent of death. Able to spread lies and discourse, and then pick off targets, either political or millitary it doesn't matter. Arachnids inherit knowledge over generations of their ancient order, inspired by the efficiency of spiders. New students to the Arachnid archetype are trained in deceit and poisons from a young age, and grow able to resist it's affects. Masters have spent their lives assassinating and killing for their one true ally, for the order of Arachnid has stood, and will stand for a thousand years.

Poisonous Fang

3rd-level Arachnid feature

Your knowledge of poisons is a boon for you in combat. Whenever you may preform a sneak attack, you may choose to instead preform a Poisonous Fang. The creature is inflicted with a deadly poison, and must make a Constitution saving throw, DC 8 + your proficiency bonus + your charisma modifier, at the start of their turn. On a failure, they take 2d4 poison damage are poisoned until the end of their next turn. On a success, they take half damage.

You may preform this ability, a number of times equal to your proficiency bonus per short rest.

At 7th level, it increases to 4d4 poison damage, at 11th level, to 6d4 poison damage at 15th level, to 8d4 poison damage and at 19th level to 10d4 poison damage.

Web of Lies

3rd-level Arachnid feature

You may spend your time sprinkling a little lie there, and a little rumour here. You may spend one day spreading rumours and then make a deception check. The DC for the deception check depends on the rumour being spread, which the DM decides if it is believable, skeptical, or outlandish. With a DC of 10, 15, and 20 respectively. The DM may choose to change the DC but must inform you of the new DC. If you succeed, then after two or more days have passed, you may roll on the table below. If you succeed the deception check by more then 5, you may roll twice.

Sowing Rumours

d6	Result
1	An important figure actively opposes the rumor
2-3	No important figures acknowledge the rumor
4	You sway one important figure
5	You sway two important figures
6	You sway three important figures

Caught in a Web

9th-level Arachnid feature

You have advantage on attack rolls against creatures that are grappled or have their movement speed reduced in anyway.

Additionally, you gain resistance to poison damage.

Black Widow

13th-level Arachnid feature

Your knowledge of poison and murder have combined to form a deadly kiss. After preforming a Poisonous Fangs, you may preform a Widow's Kiss, dealing 3d8 poison damage and causing them to become vulnerable to poison damage for 1 minute, regardless of if they were resistant or immune before. You may do so once per long rest.

The poison damage increases to 5d8 poison damage at 16th level and 8d8 poison damage at 20th level.

 

Spindle of Fate

17th-level Arachnid feature

Your abilities are such that you can weave together fate itself using the ancient techniques of the Arachnid order. You can weave events to occur onto a spindle of fate. A spindle has 10 slots, and you may choose to fill them with either a attack roll, saving throw, skill check, and an ability check in any order. You may choose whether those events occur with a boon or a curse, adding a +10 or subtracting a -10 respectively from the roll when you pick them with the spindle.

You may choose to activate or deactivate the spindle as a bonus action on your turn. While active, whenever the event occurs via a creature you can see making the appropriate roll, the event effect is applied whether it's a boon or curse. The events occur in numbered order from 1 to 10. If a day has passed since you have woven fate, the spindle unravels.

You can only weave fate once every three days.