At level one, the character gets the ability to transform into a medium sized spider at will. Spider has 50 ft of web per day, Tremorsense, speak with other spiders. Granted at Level 1.

Can see in dim or dark lighting for up to 60 ft. Granted at Level 1.

Runes appear on their left arm, and it translates to "A blessing, not a curse." Granted at Level 5.

Runes appear on their upper back that read "The Chosen of Arachne." Granted at Level 6.

You get a +2 to Str, +1 to Dex. Granted at Level 2.

Their eyes, which before were only black when terrified or angered, are now permanently black the next time they turn black. Darkvision is now out to 80 ft, but they can now only stand sunlight for 30 minutes at a time. Granted at Level 7.

The person now has spider fangs that inject venom. They drop at will and do 1d4 bite damage, plus 1d6 poison damage every hour it runs through their system. After a day, the affected is paralyzed, and after three days, dead. The antidote is the venom plus a white lily. Granted at Level 9.

Once here, when the person changes into their spider form, they will instead become a half-spider, half-human (think like a centaur). They will have all previous body changes, plus the Web and Tremorsense. Granted at Level 12.

Once at this level, the person becomes immune to all fear effects cast by other creatures or gods. Granted at Level 7.