The dragon king is of gravity element. There are two mobs, a Capsule Collector, which collects unused capsules each turn and a Gravimancer, which attacks the unit farthest away from it. More on this seemingly innocuous attack later. The Capsule Collector has no specific element and the Gravimancer is of Gravity type. The two mobs are resummoned quite frequently once they die. Only Photon attacks can deal significant damage. Thus if you don't have enough strong Photon units, go to RDK next door for Holy Dragon Otomos. I personally use 5 fully-levelled Holy Dragon Otomos. DO NOT bring healing into IDK because the Dragon King steals your healing. Regen, Life Drain, Conversion Ritual and things equivalent to these will not be stolen. There is 1 to 2 Rifts on the floor. If a unit moves into them, it will be teleported away (and hence ending your turn) and will return in 2 turns. (The PP may land on a Rift when you want to move it into position to use it. ;_; ) The pattern of the Dragon King is simple. Showing where he will hit next, Axion, Lateral (1), Showing where he will hit next, Axion, Vertical (1), Showing where he will hit next, Gravitonball, Area (1) (this one has a physical component). ...until his HP reaches 90%. Then he goes Watching and waiting, which just means he is doing nothing, Diverting more power from defence to gravitons, which just means he is lowering his mdef, Axion II, ALL!!! For the unprepared, the squad is wiped out. If you survive, the Dragon King resumes his normal pattern. The next HP threshold is at 70%. Then the next HP threshold is 40%. At this point the Dragon King will not go back to normal pattern, but hit you with Axion all attacks every other turn, each turn more powerful than the last. (Axion II -> III -> IV -> V) Currently I don't think any unit can survive Axion V without any damage reduction. The Gravimancer's attack happens before the Dragon King's attack. A unit which can normally survive may die to Axion III, just because it has been hit by Gravimancer first. (Koko Lambda is super tanky with right skill setup. Can tank Gravimancer's attack + Axion III.) Thus in this fight, it is important to decide which unit should take Gravimancer's attack. In other words, we need to know which unit is farthest away from it. (It is possible that the Capsule Collector moves the Gravimancer by one tile and changes the relative distance.) Most often it is easy to see which unit is farthest away. If there is a tie in distance, there is a specific algorithm to determine which unit will get hit. (For people who tend to get difficult configurations, this knowledge may save the run.) For lucky or SB-lucky people, they have Sayu, Schweiz... This guide is not for them. (Vertical is chosen over horizontal; right over left, up over down? Sorry, I don't remember exactly. I may get a chance to test this theory because I still need to run this dungeon for the elusive PDZ drop. ) Here are two examples. Gravimancer will hit the orange unit. Recommended units: Sayu, Schweiz, Beau'ne, Myne, Sayu, Sayu, Sayu... Whoops, I meant to recommend the following list. Regen units: Gegonago Lambda, CT+3, stealth, giga regen (cap 600), extended regen (cap 300). Jaguna Lambda, Aerial regen (cap 500). Ellvern Lambda, CT+4, CT+2, PP amp, giga regen. Bonna Lambda, Eileen Lambda, Palpa Lambda? Units with high mdef (preferably over 400): I went to http://tbs.desile.fr/#/jobs to sort mdef by descending order not taking mdef up skills' effects. Er... Shin'en Lambda, Mutoh Lambda. I don't think if you have these units, you need this guide. And one of them is of graviton type. Good old Zmages (except Jennish Lambda). High matk. Even have Self-revival. Ellvern Lambda. No mdef up skills (mdef 474 + 25, with Holy Dragon Otomo. HP 6614 with HP+20%. Sometimes survives Axion III, sometimes not. You get an estimate of how strong Axion III is.) Jaguna Lambda. mdef up skills. Really tanky. Good old SSmages. No mdef up skills. Invincible. Aerial shield. Leviathan Lambda. mdef up skills. Koko Lambda. mdef up skills. CT+4. Other units with high mdef, also preferably with high matk. Recommended skill setups: mdef up HP up Notable skills above Skills that help increase matk. (For example, Capsules for units with Metabolism.) Attack with large AOE. (This helps with filling PP gauge.) Strategy: Don't Die! If you bring in a unit with not enough mdef, equip Mog or other mdef up Otomo. Otherwise equip Holy Dragon Otomo. Avoid getting hit. Keep stacking up regen, mdef buff, CT buff. From my runs, double stacking both of Gegonago Lambda's regen skills can almost always fill HP to full after an Axion III attack for any unit I choose to bring in. Sometimes unlucky people get really bad configurations that no pincer can be made at all. Most such cases can be resolved by Stealth though. Save up PP until 40% HP threshold. Keep double pincering and use PP if you can. Choose the correct unit to tank Gravimancer's attack. Finally IDK succumbs dropping nothing... Now let's rant in unison: PDZ not dropping after #(insert your number) of runs. Oh, wait what is that?