Unstoppable beats Curse if you use it first. Curse can't remove it, and Unstoppable blocks all of Curse's effects. The catch is timing: once you're Cursed you can't use items at all, so you can't press Unstoppable or Dispel Magic to get out.
"Curse" here is the item Cursed Relic. Here's what each item does, then how they play against each other.
What each one does
- Cursed Relic (Curse): interrupts the target and removes all their non-ultimate buffs, then silences and disarms them and stops them using items for 3.25 seconds. You deal less damage while it lasts. 55 second cooldown.
- Unstoppable: for 5.5 seconds you're immune to stun, silence, sleep, root and disarm, and other negative effects are suppressed. You can't use it while stunned or asleep. 60 second cooldown.
- Dispel Magic: removes every non-ultimate negative effect on you, then heals you and speeds you up if it removed something. You can't use it while stunned or asleep. 45 second cooldown.
- Counterspell: your next parry blocks the damage and effects of enemy abilities and items, not just melee.
- Indomitable: passive. The next stun, chain, immobilize, sleep, silence or fear on you is cleansed automatically.
- Divine Barrier: removes all debuffs except stuns from you or a teammate and gives a barrier.
Who beats who
- Unstoppable vs Curse: Unstoppable, if it's already active. Curse doesn't remove it.
- Curse vs Unstoppable or Dispel Magic you haven't used yet: Curse. Both are items, and Curse stops item use.
- Unstoppable vs stuns: Unstoppable. That includes Knockdown's delayed stun and the stun from being parried.
- Dispel Magic vs stuns: the stun. Dispel can't be used while you're stunned.
- Dispel Magic vs ultimates: the ultimate. Dispel only removes non-ultimate effects.
- Divine Barrier vs stuns: the stun. It removes everything else.
- Counterspell or Indomitable vs The Doorman's Hotel Guest: either one stops it.
Indomitable is passive, so it needs no key press at all: it's the one answer here that works even when you react too late.
For more on parrying, see what you can parry.
Quick answers
Does Curse go through Unstoppable?
No. If Unstoppable is already active, Cursed Relic doesn't remove it and none of its effects apply.
Can you use Unstoppable while Cursed?
No. Curse stops item use, so you have to activate Unstoppable before the Curse lands.
Can Dispel Magic remove a stun?
No. You can't use Dispel Magic while stunned or asleep, and it never removes ultimates.
Can Counterspell block The Doorman's ultimate?
Yes. Blocking Hotel Guest with Counterspell's parry stops it, and so does Indomitable cleansing it.
Can you silence Victor's ultimate?
No. Victor's Shocking Reanimation can't be silenced.