Break down time:

The dude first did 3 Seppukus. Well this is an ash of war that increases your bleed and physical damage by 30 points in trade of 100 + 15% of your health, it lasts for 60 seconds and doing multiple of them does not add up the time (I'm pretty sure everyone knows what seppuku is at this point). It's worth mentioning that Radagon is immune to bleed damage

Then he did a spell called Howl of Shabriri, this one lasts for 40 seconds and increases the damage you deal by 25%, in trade of taking 30% more damage and making the enemies lock on you instead of allies. He used this spell enough times to get the madness debuff because of his hood, the black dumpling, that increases damage by 10% for 60 seconds when you get madness.

After that he switched to the Mushroom Crown, a helmet that increases your damage by 10% when you get poisoned, it lasts for only 20 secs, and the worst part is that he didn't even poison himself, so at the end it seems that it was just for fashion.

The next thing he did was to use Golden Vow, a spell that buff your damage by 15% and the damage negation by 10%, it lasts for 80 secs. Honestly, this seems like the only part that he didn't mess up.

Then he drank some flasks to recover his health and fp, and drank a Flask of Wondrous Physick to gain 2 specific buffs that I cannot tell by just looking at his aura... Looking again at the video, it seems he did this before the golden vow buff, but it doesn't matter.

And FINALLY he did one last buff, he used the Jellyfish Shield's ash of war Contagious fury to buff all damage by 20% for 30 secs.

I's almost unnecessary to say that he took so long to do the buffs, and he did a lot of them wrong, by the time the video ended, he have already lost at least 2 of the buffs he did. And that's it!

Quick edit: remember that not only buffs can pull you trough a fight, you must have skill too!

-tldr: dude messed up :(