Dreadmaw Umbra seems reasonable. I could see that as a limited relevant rare in a set.
Precognative Insight is undercosted, should be 1U to 2U for 2 draws with scrys.
Shaman seems fine, I like that you found an interesting way to make a tribal card that I don't thinks been done before.
For Charsi: First, Hexproof doesn't work as a red/black ability, but I see why you put it there. I'd instead make it "Protection from Devils" and you could even lose the hellbent aspect. Also, make the self-discard non-random, no one likes to play with random discard and it becomes more utility for the deckbuilder as well.
Northwind Swan should trigger on enters the battlefield, not on cast. As written, the trigger is basically uncounterable itself since countering the swan wouldn't stop the trigger. Its also undercosted, since Man'o'war is basically the same cost, without flash, flying, or the ability to bounce a spell. Should be 2UU to 3UU.
For Cht'lari, I like the direction, but you should definitely adjust the power of the trigger steps, especially the second one. As it is, hitting 8 counters means you get to untap a bunch to play more spells, then untap again on your extra turn. You should also consider making it "you may remove any number of Doom counters you have." so that you aren't forced to remove the only 2 counters you have for no effect for instance. Lastly, I personally think its more aesthetic to go 2/4/8 than 3/5/8.
Try this:
When Cht'lari enters the battlefield, you may remove any number of Doom Counters you have. If you remove 2 counters in this way, draw three cards and discard three cards. If you remove 4 counters in this way, also gain control of target non-land permanent. If you remove 8 counters in this way, also take an additional turn after this one.
Lastly, do a typo pass, like fixing "beginning" being misspelled in a couple of places, missing commas, etc.
Dreadmaw Umbra seems reasonable. I could see that as a limited relevant rare in a set.
Precognative Insight is undercosted, should be 1U to 2U for 2 draws with scrys.
Shaman seems fine, I like that you found an interesting way to make a tribal card that I don't thinks been done before.
For Charsi: First, Hexproof doesn't work as a red/black ability, but I see why you put it there. I'd instead make it "Protection from Devils" and you could even lose the hellbent aspect. Also, make the self-discard non-random, no one likes to play with random discard and it becomes more utility for the deckbuilder as well.
Northwind Swan should trigger on enters the battlefield, not on cast. As written, the trigger is basically uncounterable itself since countering the swan wouldn't stop the trigger. Its also undercosted, since Man'o'war is basically the same cost, without flash, flying, or the ability to bounce a spell. Should be 2UU to 3UU.
For Cht'lari, I like the direction, but you should definitely adjust the power of the trigger steps, especially the second one. As it is, hitting 8 counters means you get to untap a bunch to play more spells, then untap again on your extra turn. You should also consider making it "you may remove any number of Doom counters you have." so that you aren't forced to remove the only 2 counters you have for no effect for instance. Lastly, I personally think its more aesthetic to go 2/4/8 than 3/5/8.
Try this:
When Cht'lari enters the battlefield, you may remove any number of Doom Counters you have. If you remove 2 counters in this way, draw three cards and discard three cards. If you remove 4 counters in this way, also gain control of target non-land permanent. If you remove 8 counters in this way, also take an additional turn after this one.
Lastly, do a typo pass, like fixing "beginning" being misspelled in a couple of places, missing commas, etc.