Advice on advancing a Gearghost to CR 10?

[AtlasSniperman]

Hey guys,
I'm workin on a campaign and would like for the midgame boss to be an advanced gearghost. Any ideas how I should go about advancing or improving one?

I have plenty of time but i want to make sure any relevant or necessary clues are included along the way.

[aimlessPolymath]

There are some general guidelines here (https://www.d20pfsrd.com/bestiary/rules-for-monsters/monster-advancement/).

[Thealtruistorc]

Most straightforward way would be to give them class levels, maybe in rogue, investigator, bard, or sorcerer.

[Eldariel]

So it's a CR5 by default and you need to double its CR. First of all, it only seems logical to double its HD with everything that entails (feats, HP, skills, saves, BAB, etc.). Might want to add a bit to its natural armor and double its DR to DR 10/- as well. Second, raising its key abilities, that is the Create Trap at least, to twice the CR (CR8). Then the SLAs should probably be pumped by 5 CLs up and perhaps consider adding e.g. Fabricate to the 3/day list, and perhaps something thematic like Create Pit, Passwall or (Greater) Dispel Magic. And perhaps give it Quicken SLA or something of the sort. I actually had to doubletake the fact that it's actually not incorporeal. Hrm. Peculiar.

[AtlasSniperman]

There are some general guidelines here (https://www.d20pfsrd.com/bestiary/rules-for-monsters/monster-advancement/).
They don't really help adjudicate improving the special abilities. But thanks.


Most straightforward way would be to give them class levels, maybe in rogue, investigator, bard, or sorcerer.
As tempting as it is, I already have several monsters with class levels. That and the gearghosts powers aren't reaaaally added to by any class, so it'd end up looking like a weird podge.


So it's a CR5 by default and you need to double its CR. First of all, it only seems logical to double its HD with everything that entails (feats, HP, skills, saves, BAB, etc.). Might want to add a bit to its natural armor and double its DR to DR 10/- as well. Second, raising its key abilities, that is the Create Trap at least, to twice the CR (CR8). Then the SLAs should probably be pumped by 5 CLs up and perhaps consider adding e.g. Fabricate to the 3/day list, and perhaps something thematic like Create Pit, Passwall or (Greater) Dispel Magic. And perhaps give it Quicken SLA or something of the sort. I actually had to doubletake the fact that it's actually not incorporeal. Hrm. Peculiar.
Thanks, this ll help a lot! I was uncertain how to deal with +cr and it's special abilities, having never improved a monster by HD. This all looks to be solid advice, thanks.

[AtlasSniperman]

Well, here's what I think looks reasonable. I took Eldariel's advice most, but upon checking the monster advancement rules aimlessPolymath provided I found that it was probably more likely to be CR 9. Erring on the side of awesome, I threw on a template that is not technically legal for a gearghost but I felt it works really well.

Thanks guys!

Killian de Moure
Floodslain Gearghost
CE Tiny Undead
Init +6; Senses darkvision 60 ft.; Perception +20
DEFENSE
AC 19, touch 14, flat-footed 17 (+2 Dex, +5 natural, +2 size)
hp 147 (14d8+84)
Fort +9, Ref +8, Will +12
Defensive Abilities channel resistance +6, rejuvenation; DR 10/—; Immune undead traits
OFFENSE
Speed fly 40ft(perfect), swim 30ft.
Melee 2 slams +10 (1d4-1 plus drowning touch)
Space 2-1/2 ft.; Reach 0 ft.
Spell-Like Abilities (CL 14th; concentration +14)
At Will--detect magic, mending, telekinesis
3/day--make whole, fabricate, transmute rock to mud
1/day--greater dispel magic
STATISTICS
Str 8, Dex 15, Con -, Int 15, Wis 16, Cha 21
Base Atk +10; CMB +10; CMD 19
Feats Flyby Attack, Improved Initiative, Lightning Reflexes, Skill Focus(Stealth), Toughness, Deadly Trap, Trapper's Setup, Skin Suit
Skills Craft (traps) +24, Disable Device +9, Fly +26, Knowledge (engineering) +15, Perception +20, Spellcraft +19, Stealth +30, Swim +10, Survival +11; Racial Modifiers +8 Craft (traps), +8 Swim
Languages Aklo, Common, Undercommon, Aquan
SQ create trap, resetter, flash flood
SPECIAL ABILITIES
Create Trap (Su): Once per week, a gearghost can create a trap of CR 7 or lower regardless of cost, materials, or skill checks. Two or more gearghosts working together on a trap can increase the maximum CR by 2 for each additional gearghost working in concert. For example, three gearghosts working together can create any CR 11 or lower trap in a week. Killian typically uses this ability to create lesser traps from whos parts it can use the fabricate spell upon to create more powerful traps. When casting fabricate to create traps, Killian may always take 10(automatic DC 34 means it can create any trap of CR 15 or lower).

Rejuvenation (Su): A destroyed gearghost reforms in 2d6 days. To permanently destroy a gearghost, holy water must be poured over its remains within the area of a hallow spell. To complete the destruction, every trap within 100 feet of the remains must be successfully disabled or destroyed before the gearghost is completely destroyed.

Resetter (Ex): A gearghost can reset traps and keep them repaired with supernatural efficiency. A gearghost can reset a trap with a repair or manual reset as a move action. If a trap has an automatic reset that is longer than immediate, a gearghost can reset that trap as a free action.

Crashing Waters (Su): Once per day, a floodslain creature can instinctively summon a spectral echo of the rushing waters that created it. This mass of phantom water slams the floodslain creature from behind, carrying it forward at up to three times its normal speed and enabling it to charge a single target. These waters also impact all creatures near the end of the floodslain creature’s movement, pushing them back. This acts as a bull rush; the floodslain creature attempts a single combat maneuver check against the CMD of each creature within 10 feet of the end of its charge. This bull rush attempt doesn’t provoke attacks of opportunity.

Create Spawn (Su): Any creature killed by a floodslain creature rises as a floodslain creature if it’s left immersed in water for 24 hours. These spawn aren’t under Killian's control.

Drowning Touch (Su): The slam attack of a floodslain creature partially fills a living victim’s lungs with water. The victim must succeed at a Fortitude saving throw (DC 22) in order to cough up this water or become fatigued for 1d4 rounds. A fatigued creature that fails this save becomes exhausted instead. An exhausted creature that fails this save is staggered and falls to 0 hp. A creature at 0 hp that fails this save drops to –1 hp and begins dying. A creature killed in this fashion appears to have drowned.

Panic (Su): The dead eyes of a floodslain creature are frozen with shock and fear. The floodslain creature can induce fear in a living victim as a standard action. Targets must succeed at a Will saving throw or become shaken for 1d6 rounds. A creature can be affected by Killian’s panic attack only once every 24 hours.

Flash Flood (Su): A floodslain creature is constantly surrounded by an echo of the disaster that originally took its life. Water streams from Killian’s body, forming a 30-foot-radius pool that renders the ground in that area slick and muddy and increases the DCs of Acrobatics checks made in the area by 5.

Powerful traps: All traps created by Killian de Moure either increase their critical multiplier by 1, or gain a +4 bonus to confirm critical hits. Additionally, any trap Killian de Moure triggers itself gains a +2 bonus to either attack rolls or save DC(as applicable)

Skin Suit: Once per day as a full-round action, Killian can cloak its body in a thin, fleshy suit that gives it the appearance of a young human child. This doesn't effect its ability scores. When wearing this skin suit, Killian is masked as though by a constant undetectable alignment spell and has the aura of a living creature instead of an undead one for the purposes of detect undead and similar effects. While this ability is active, Killian's Flash Flood ability is suppressed. The skin suit dissolves back into the flash flood ability at sundown, though it can remove it any time as a standard action.

ECOLOGY
Environment any urban or underground
Organization unique
Treasure standard
Killian de Moure was a greedy thief who, upon discovering the location of an immense treasure horde, lost his life to a unique drowning trap. This trap torturously kept him from dying by drowning for two days, all the while making it impossible for the young thief to free himself. Eventually, he drowned to death after passing out of exhaustion. While he was trapped however, the guild to which he had sworn his allegence was attacked. Due to Killian de Moure's unexplained absence, many of his guildmates blamed him for the attack. They died blaming him for their loss and in the belief that Killian had 'sold them out'. This communal anger and hatred, fused with the torturous means of Killian's death, brought the young thief back in the form it bears today.

Killian is a sick, malicious creature that wants only the suffering and death of others. Often disguising itself as a child in order to lure helpful and honourable people to its lair, Killian takes great pleasure in torturing creatures in unique and agonizing traps. Creatures who survive Killian's games often become broken souls, who's only desire is to bring Killian more victims to sate its appetite and prevent their own torment resuming. Creatures that die at Killian's hands become floodslain, and wander the ever growing halls of the lair, unintentionally testing many of Killian's experimental traps.

The Lair of Killian de Moure is a muddy hive. Similar in appearance to a giant ant or wasp nest, bore into the very rock and seeded with deadly contraptions of ever growing complexity. The treasure the young thief had died trying to retrieve has since become lures and snares in the various devices, and has been joined by the remainders from the floodslain Killian sees no further use for.

[Eldariel]

You forgot the caster level increase for the SLAs; they should be CL 14 since base Gearghost is CL 9. Looks good though. Don't forget to map out the traps he's created over his time with the Create Trap and through mundane means :)