This is kinda overdue, and I'm not the first person to beat the Crimson Orochi this time, but I figure I might as well make an incredibly-easy-to-understand guide to my Crimson Orochi tactics for guaranteed quick and painless clears.
This should be your setup, or something similar:
Ci Cerca, to my knowledge, has the highest raw Crush value of any gun in the game, so your options are either that or a fully-upgraded Iblis (Demiurge blast gun) for the attribute bonus).
Deicide is the key component here, as it gives you the necessary Blood Rage pledges.
Trigger Happy is necessary, which is why Goddess of War's Gun and/or Ci Cerca should be used (I deleted the skill containing Trigger Happy from my Ci Cerca due to its downsides, so that's why I needed an alternate source).
Hidden Master is for Hidden Attack, so if you already have Hidden Attack on another piece of equipment, you don't need Assassin.
Link Support should be you and Julius.
Anyway, down to the nitty-gritty:
When you enter battle, immediately activate Blood Rage and select the first two and last two pledges. This should give you a 924% total multiplier.
Once you trigger the activation process, AIM DOWN THE SIGHTS AT THE CRIMSON OROCHI (do not simply fire from a neutral position, as the bullet will hit the ground prematurely and not go off) and fire this bullet:
If you have Frugal, you should be able to get off another shot of this bullet before Blood Rage triggers and the Crimson Orochi starts running towards you. Either way, once BR begins, start rolling towards the CO, and when you get around 3-4 (CO) lengths away from it, stop rolling and start spamming this bullet:
Just keep firing and do not let up. The constant explosions will make it hard to see, so pay attention to the minimap to see where the CO is. If it starts running away, roll after it and fire as soon as it comes to a stop. It doesn't run away in all instances, though, but just in case it does, be prepared to pursue.
You SHOULD NOT fail to kill it before BR runs out, but in the event that you do, two more shots of that second bullet should do the job.
And that's that! I hope I am able to help those of you who can't manage to beat this thing!