If you're pushing Holy Fire in Path of Exile 2, you'll find out fast that a "pretty good" crossbow doesn't stay pretty for long. A Rage Core Siege Crossbow with +7 to projectile skills and some flat fire is a strong start, but it's still just a start, and it can chew through PoE 2 Currency if you go in messy. The whole plan is simple on paper: take a good base, use the Well of Souls, and force the kind of Desecrated Modifier that actually changes your damage ceiling, not just your tooltip.

Get your kit together first

Don't walk up to the Well with an empty backpack and vibes. Set yourself up so every click has a point. The Omen of Sinistral Necromancy and the Omen of the Liege are the usual backbone because they tilt the odds toward those rare Amanamu-style outcomes you're really chasing. Then there's the one people skip and regret later: Omen of Abyssal Echoes. That reroll on reveal is huge. It's not "nice to have." It's how you avoid locking in a dead mod when your first set of options shows up and none of them match what your build actually wants.

Desecrate the crossbow the right way

Use a Preserved Jawbone to desecrate the crossbow and open the special mod slot. At this point, be strict. If you're building around Holy Fire grenades, you're hunting a prefix that pushes your burst, not a random quality-of-life roll. You'll see tempting stuff—fire penetration, extra projectiles, even some niche utility—but the dream is a top-tier grenade prefix. Big increased grenade damage with duration is the kind of roll you feel immediately in maps. Packs stop being "a few throws," and turn into "one throw, keep moving." That's the whole reason you're doing this in the first place.

Finish the suffixes without bricking it

Once the prefix is locked, the item finally starts to look real, but suffixes can still make it annoying to play. A Greater Exalted Orb, or an Omen of Greater Exaltation, is where you take the gamble. What I'd pray for, every time, is physical damage leeched as mana. It's not flashy, but it fixes the worst part of grenade spam: running dry at the exact moment you need to keep pressure up. If you miss and land something like accuracy or light radius, it's not the end of the world, but it is a gut punch. After that, clean up the basics—Whetstones for quality, then sockets with Artificer's Orbs so the weapon actually fits your setup.

What makes it feel like a real endgame piece

The difference between an "okay" craft and the one you keep for weeks is how it plays under stress. Boss phases, cramped arenas, bad mods on the map—this is where a grenade-heavy prefix and a useful mana suffix earn their spot. You're not crafting for screenshots; you're crafting so the build stays smooth when everything goes sideways. If you're stocking up to take a few serious swings at the Well, I've seen plenty of players mention buy game currency or items in U4GM and then point to u4gm poe as the quick way they keep attempts rolling without stalling their entire league plan.