I’m not familiar with the lore, but if you’re right, props to you for coming up with an alternative solution. I had a different solution in mind.
Forum Game: Riddles
Is it Shadow Sister Kelaino??
Nope, you’re very close though.
Shadow Dancer? filler
Urgh I should have considered the potential options more carefully. That does fit closely, though I mentioned in an earlier comment that the strength refers to giving attack, rather than health.
My guess is Shadow Reflection. Doesn’t fit perfectly, but it’s the best I could come up with.
Death fire cresedo?
The “gatherd shadows” follow the unit and give it strength… And you need light(bright) to cast a shadow
On second thought, it actually fits very well.
“I follow where your path is bright” - refers to the Shadow being cast
“Despite my darkened heart” - Shadow Reflection seems quite dark to me
“I give you strength to help you fight” - +5 Attack
“I’m yours, though we’re apart” - The Reflection is you, yet it is apart
Bingo, you got it and explained it exactly as I had in mind. Well played!
It turns out multiple cards fit closely though which I probably should have been careful about, oops.
I’m no damn poet, but here we go.
The arcanysts have fallen
All fires have gone out
Now pray to the heavens
You’ll find me, have no doubt
Heaven’s Eclipse?
Nope. 
Sunriser? more characters
Nope.
more ch
So something that has a Dying wish that summons something smaller than it’s self…
Doltas:
Line 1: Check
Line 2: Not so much
Line 3: Kinda
Line 4: Yes, Close to the general
Sarlac:
Line 1: Yes
Line 2: Still no
Line 3: Kinda
Line 4: Not really
Reaver:
Line 1: Yes
Line 2: Yes, Celerity
Line 3: Yes
Line 4: No
Jaxi:
Line 1: Yes
Line 2: Yes, Ranged
Line 3: Used to be
Line 4: I still don’t get that one
So I would say Jaxi.
A wicked Witch, but without the hat,
or the broom, cauldron or the cat.
In fact, a man, but no ordinary kind,
for red, liquid blood in his veins is something you wont find.
The riddle in the OP was the starting riddle, not the current riddle, at post #450, and was solved a while ago
. Aside from that, congratulations for solving it correctly! It was indeed Jaxi. I worded the last line kind of weirdly and meant that each player hopes that jaxi will spawn closer to them. Reaver is a good candidate for the solution, too, but the third line specifies “a smaller friend” rather than multiple. Jaxi spawns a single mini-Jax.
first thought is Heavens Eclipse, but you said no to that…
I keep coming back to all fires have gone out. If i asume you mean phoinex fire, then maybe laturn fox.
he isn’t an acarnyst, tho played in acarnyst decks.
he would re’kindle the fire
the last bit kinda looses it though…
Heavens…
Spiral kinda works.
it’s is a finisher you would play after most you minions have gone.
the fires bit is kinda iffy, but if you consider it to just be a another way of saying it is late game, that it kinda works.
and i know i do all kinda praying when the enemy general is on 8 health 
so one of the 2 i think.
also, i can’t be asked to proof read this…
ooooooooooooooooooooooooooooooook, this makes sense now. ty
any ideas on mine or was I too cryptic?
A riddle should be cryptic, yours is fine. I like it a lot actually.
My guess is bloodtear alchemist? An alchemist is a sort of witch, though I’m not sure what runs through his veins.