Just a very quick guide on suffering through ripper demons for beginners.
Gear:
Weapon: Enhanced darklight
Offhand weapon: Drygore
Helm: Slayer Helmet/Malevolent (on task)
Neck: Souls/Blood amulet
Torso: Malevolent/Tetsu
Waist: Malevolent/Tetsu
Gloves: Best available to you
Boots: Best available to you
Ring: Ring of Life
Aura: Vampyrism/Penance
Inventory:
Familiar: Legendary pet (not worth using a familiar for me, death is too probable)
Strongly recommended abilities: Freedom, Devotion, Surge/Escape*, Anticipation
Turn accept aid for teleports off.
Be patient - you'll probably die a few times until you get the hang of it (and even then, be careful).
Play it safe and bring a ring of life and teletabs. It's easy to say keep your health above 50%, but mistakes will happen and it can get overwhelming. Do all your killing on an empty world. The death mechanic will hit you for 700+ several times until the animation ends or you move - even if it's another player's demon. If you get under 50% and get piled by demons, teleport out. House teleports are best since it's a safe death.
Use protect from melee and turmoil. Try not to use any armor lower than Torva/Tetsu.
When the demon's adrenaline bar is full, be ready to move. It's not guaranteed to use the one hit kill immediately, but can at any time after full adrenaline. I recommend using Surge or Escape, as clicking another ripper demon while dodging the special is a very real possibility. After you move, you can either run towards it to attack or wait for it to attack you. The latter will result a bleed being inflicted on you - get rid of it with freedom.
Run away after it dies. A legendary pet helps greatly with looting.
There's currently a glitch where, if you die, the demons nearby will pile on you when you re-enter the cave. If you're returning after death, use anticipation before entering. Exit and enter the cave to fix being piled.
Again, be patient and don't give up. It's tricky at first, but once you get the hang of it, it's not too bad.
*Instead of using these abilities, you may use the Prism of Salvation. Set it up a decent distance away from the demon you're fighting. When it jumps, click on the prism. After it comes back down, run away from the prism or towards the demon. Click the prism again when the demon dies.