His main physical fighting style revolves around the Battle Jump feat, the most iconic usage of which sees him shapechanging
into a (MM3) Wood Woad
-ing (free action) multiple times to scan an entire forest, exiting/falling out of a tree at 10ft. of altitude above the target enemy to trigger Battle Jump
, and then Treewalk
-ing again to teleport back into the tree and avoid falling damage. If the enemy is not close enough to any properly-sized tree, he can try either shapechanging into a decent bullrushing animal form, casting a spell that bull-rushes/pushes creatures, or tactically using Arboreal Transformation. Basically, Kobayashi is nigh unbeatable in physical combat within a dense forest. Also, I'm not sure if he'll get bonus points for accidentally breaking Quall's Feather Token (Tree), but I just feel the need to mention such a fact.
After Kobayashi turned over a new, darker, leaf, he began showcasing easily recognizable M/O and memorable feats to increase his crusade's infamy, with the hope that like-minded individuals join his cause, or even just commit similar types of attack in his name; humanoids in the vicinity of his attacks would be gone missing, while left behind in his wake were rows of beautiful thorny bushes of different varieties, depending on location--roses, blackthorns, mountain pines, common hollies, fuschia-flowered gooseberry, and firethorns--and sometimes accompanied by a huge oak tree or two. Some of his better known feats of renown were 1. disposing, in a blink of an eye, thousands of enemies hunting him within a forest, and 2. completely submerging dragged enemies in lava and coming out the lake of fire completely rejuvenated instead of harmed. A successful Spellcraft check might show that discovered oak trees are actually people turned to trees via an Arboreal Transformation effect, while successful Knowledge (Nature) checks will identify specific monsters of nature that exhibit related abilities separately: the Splinterwaif fey can turn humanoid/fey corpses into bushes, the Wood Woad plant can move quickly from tree to tree, and the Phoelarch monstrous humanoid can be healed by fire.
A large part of Kobayashi's other combat methods aren't exactly the most optimal; rather, they are based on, in his perspective, things that most illustrate the wrath and vengeance of nature (including usage of the elements, since the inner planes are canonically the building blocks of the material plane's "nature"). Mass destruction effects such as tornadoes, tidal surges, fissures, and explosions, work to evoke a sense of nature's uncaring power, while precision strikes, such as targeted impalement, spontaneous combustion, asphyxiation, and drowning, work to evoke a sense of Kobayashi's personal retribution from individual people's violation of nature.
Spoiler: Examples of such themed spells from the PHB and the SpC
2nd: Fog Cloud, Kelpstrand
3rd: Crumble, Dehydrate, Downdraft, Heatstroke, Wind Wall
4th: Eye of the Hurricane, Flame Strike, Murderous Mists, Rushing Waters, Spike Stones
5th: Control Winds, Inferno, Wall of Sand
6th: Blood Sirocco, Drown, Extract Water Elemental, Stonehold, Tidal Surge
7th: Animate Plants, Control Weather, Fire Storm, Storm of Elemental Fury, Storm Tower, Swamp Lung, Water Spout
In a nutshell, Kobayashi feels like a Druid with lower-level spells, superior shapeshifting across the board, and no animal companion/s. However, he's most suited to play like a guerilla fighter, as befits the eco-terrorism angle, not shying away from unloading all his daily resources in one big fight and bailing out easily if it doesn't go his way. He's not too optimal, preferring visually-engaging style and a certain degree of ham, but he is at least aware of it and even deliberately prefers it to better showcase the raw power of nature.
Spoiler: CR5: Panacea Plintt, the green guardian (Sweet Spot)
Kobayashi was a paragon of selfless heroism for the sake of protecting nature. Not only did he protect the small forest where his home-tree resides, but he also pledged support to a group of foreign nature defenders, heeding their calls for help on their direst of moments. He became a popular hero and legend amongst the commonfolk associated with these allies and was referred to in the common tongue as "Panacea" Plintt, Plintt being a name derived from the sound of twisted wood.
- Minionmancy with diplomacy (coupled with sense motive) for intelligent creatures and Wild Empathy for animals
- Access to all Wu Jen wood spells 1/day, including Arboreal Transformation, to defend and nurture the forests
- CL8 Shapechange (Supernatural) is pretty crazy even if used thematically (i.e. assuming the form of nature-related creatures):
- Assassin Vine for Entangle at will
- Fey forms for CHA madness and save-or-suck/die
- Plant/Vermin/Animal forms for poison
- Animal/Giant/Monstrous Humanoid forms for beatsticks (especially felines and certain trolls for pounce + Battle Jump)
Spoiler: CR10: "Gaea Ma Shakti De"
Kobayashi has already fallen by now, exacting cruel and brutal revenge on those who exploited nature without thought or care (i.e. those that practice wasteful usage of natural resources; e.g. spellbook users, scroll-spammers, artisans for vanity or social-status items, etc.). Being turned into a Gravetouched Ghoul gives him more freedom by breaking his dependence to his now-destroyed home-tree. Due to how vaguely-enough defined a "corpse" is, he can now "optimize" "recycling" an enemy humanoid under the effects of Ghoul Fever by taking out its (or its corpse's) heart, transforming the dead heart into a new small thorny shrub, and then letting the rest of the body rise as a heartless ghoul within the grounds of his next site of attack.
- CL8 2nd-level druid spells; Updraft for a swift action Battle Jump enabler
- CL12 Shapechange now has access to 12HD forms
- Multiattack benefits forms with multiple natural attacks, especially with Pounce and Battle Jump
Spoiler: CR15: "I heard you went insane." "I heard you were a shrub."
At this point, he also begins recruiting in his crusade other feyfolks and elementals, which he considers to be fellow spirits of nature. He turns the corpses of uncooperative feyfolks into shrubs to serve as example to others.
- Detect Spirits to search for these allies, and then Chastise Spirits to punish those being less than cooperative, with Blessing/Warding of the Spirits used to defend against those who fight back.
- Guide Magic for one, free, concentration-duration spell at a time for some (summoning) spells, "wall" spells, and detect good/evil/spirit SLAs
- Spirit Form for survivability via incorporeality without shapechanging
- CL13 5th-level druid spells
- Spike Stones, Inferno, Rushing Water, and Control Winds for thematic, flashy spells
- Extended Lion's Charge for unconditional pounce for 2 turns
- Dimensional Jaunt for a standard action Battle Jump enabler, so Updraft + Dimensional Jaunt = 2 Battle Jumps
- Improved minionmancy with fey/elemental allies and summoning/trean-imation spells
- CL17 Shapechange
Spoiler: CR20: Plants and Zombies
In addition to his own powers and abilities, at this point, Kobayashi will have massive forces of all sorts at his disposal to pose a serious threat on entire civilizations--from his personal minions (animals, treants, and zombies) to allies and underlings who pledged allegiance to him and his cause (feyfolks, elementals, druids, spirit shamans, etc.)
- CL18 7th-level druid spells:
- Control Weather, Storm of Elemental Fury, and Swamp Lung for more awesome visuals
- Liveoak and Animate Plants spells for minionmancy and free trees for your uber Battle Jump
- Shuffle spell for a move action Battle Jump enabler, so Updraft + Shuffle + Dimensional Jaunt = 3 Battle Jumps
- Mindsight when using forms with Telepathy, for better detection of enemies and potential recruits (Mindsight reveals creature type!)
- Fell Animate "recycle" more enemies, giving heartless (as the ghoul above) zombies 100% under your command
- Improved minionmancy with fey/elemental allies, summoning/trean-imation spells, and Fell Animate feat.
- CL22 Shapechange