Crucible Forge
This article describes new Path of Exile content released in version 3.21.0. Information may be missing or incorrect.
Please expand this article so that it provides complete and accurate information.
Crucible forge is the mechanic added in the Crucible league that allows you to unlock and level up skill trees on a weapon or shield (or El'Abin's Visage).
The skill tree of a weapon is revealed when you gather enough Crucible Forge xp through charging one or multiple encounters to unlock the first node.
You can stop charging the forge at any point, and continue after. If the first node is unlocked, then this allows you to see the exact xp amount you get for completing the encounter, if you hover the bar at the bottom of the mechanics dialogue window.
Clicking on a tree node starts charging the forge.
Charging increases the xp for the item skill tree but also increases the fight difficulty, spawning more monsters (in a visible effect) and potentially increasing their overall strenght (needs confirmation?).
If you charge for too long, the mechanic starts the fight immediatly, otherwise the fight starts once you leave the circle around the forge. This enables you to setup your buffs, totems and other mechanics you might want to prepare for the fight.
Notably a conversion trap can take some aggro of you by converting a monster of any strength to your side for a limited amount of time, diverting damage from you and adding a low amount of damage to your side of the fight.
Tree limitations
Weapons trees usually have offensive nodes.
Shields trees have defensive nodes.
In each tree only one node at each tier can be unlocked.
