To clarify regarding Astel, there are two versions of the boss. One is called "Naturalborn of the Void" and is fought near the end of the Ranni questline, and is a perfectly fine and fair boss. It has big tells, and the only tricky move is a grab attack which can still be dodged fairly consistently, and if not, doesn't kill in one hit anyway with decent vigor.
There is another version in a Consecrated Snowfield dungeon with beefed up stats, which make the fight last much longer. It's still the same otherwise, except its grab attack is different and much harder to dodge: instead of just grabbing you, it will spawn 10 copies of itself which will all try to grab you at once, and will connect with you anywhere in the room. If you fail to dodge, it's a one-hit kill at full HP with endgame stats. To be clear, the grab CAN be dodged, but it's much trickier, and you can only practice it once every 5 minutes since he only does it in the second phase.
I found the 2nd fight a bit frustrating since there was a lot of RNG as to how often it does the grab. Not beyond the pale for Soulsborne games, but a bit unbalanced still.
And I was surprised to see that apparently, some feel the OHKO Consecrated Snowfield version is easier? Not my experience!
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