A build in UNDERDEEP is one damage pair plus a priority order: a single-target hit deals POW plus SPD, an area hit deals half of MAG plus SPI, so the Underdeep power speed vs magic spirit damage split is decided by the weapon you equip, not by how rare that weapon is. Pick a pair, point your gear and job levels at it, then cover the dungeon thresholds underneath it.
Single target or AOE: pick one damage pair
- Single target: equip two weapons that boost the same physical stat, then put job points into that stat. It is the simplest way to reach a two-hit kill on a boss.
- AOE: equip two weapons that boost the same magical stat and share an element, then put job points into that stat.
AOE is the stronger endgame setup because it is what lets you exploit elemental weakness and use skills that boost your weapon's element. Two AOE weapons boosting the same stat and element is the strongest setup you can put together - and the element you choose decides which monsters you can actually break, so the elemental weakness rules come before the weapon hunt.
Whichever style you pick, most bosses still take at least two hits, so budget for two hits rather than assuming a one-shot.
Underdeep build guide: the priority order for a build
- The stat your weapon boosts.
- Dexterity.
- HP.
- Sense and Toughness.
- Everything else.
Points beyond the fifth slot are close to wasted, because Intelligence, Negotiation and Charisma only matter for one-time event checks on the map and never touch damage, drops or survival.
How much mitigation and HP to take
Beyond the attacking stat, take enough Sense, Dexterity and Toughness to clear the per-dungeon breakpoints, and take enough HP to survive two hits from the bosses of the dungeon you are farming. The exact numbers are per dungeon and change as you go deeper, and they are laid out in the per-dungeon threshold tables.
Prefer jobs that give HP alongside Dexterity or your attacking stat, so a single job slot pushes two useful numbers at once instead of one.
Jobs and skills that fit the plan
Jobs raise stats and nothing else - they award points into two stats and give no new skill, ability or action, and they can be reset from the same panel if you pick badly. Skills are bought separately with Orbs, and they are where you round out Dexterity, Sense and Toughness, because Orbs are far more common than job experience points. The job list and stage structure are in the jobs and stages guide, and the Orb budget is in the skills and Orbs guide.