Techniques of Power
Go and read Alternatives to Boasts.
In our most recent open table session, one of the characters wrestled a mighty winged ape warrior in a bid to prove himself worthy of the great ape's tutelage. He ended up tapping out of a vicious chokehold but put up enough of a fight that the warrior agreed to train him once he was strong enough. I've been reading and thinking about non-linear forms of advancement (see An Alignment Post) and I think that's let me be drawn into providing more grist for that particular mill - a mention of tutor training and supernatural advancement by oldhawkeyes and nobody on the Gay Beholder Discord was the last straw. Find a master who will teach you, and learn a not-Feat.
So, having painted myself into a corner, here are some Feats of Power for characters to learn, and to fuel with the fires of their ambition.
Arts of War
Martial techniques for splitting skulls and spilling blood.
Ego Killer
Strike your target with a stick or your open hand, hard enough to hurt but not harm. Avoid their attack and revel in their frustration and rage. Strike them again and stay beyond harm. If you strike them a number of times equal to their HD+1, and avoid taking damage from them in turn, watch as the humiliation hollows them out and the heart ceases to beat. Only works with an audience.
Fierce Horse Soul, Great Chariot Rider
The enemy must attack you, successfully or not, each round you recite the mantra. You may end your recitation and attack after a minimum of 3 rounds. For each round spent reciting, your attack deals an equivalent number of d6+HD damage if it hits, half if it does not.
The Forbidden Taste of Life
Fall upon your enemy with your very teeth, that their lifeblood shall fuel your lust for battle. Attack as if with a Light weapon - regain hp equivalent to the damage dealt+HD. Supping twice in a day from the same type of creature unbalances the humours, causing sickness.
Guardian of the Gate
Weave a web of death with your weapon for HD rounds. You are immune to arrows and similar projectiles and take +4 to defence against melee attacks. All within melee range suffer 1d6+HD attacks. You can move at quarter speed while performing this dance, such is the strain. You are exhausted for the rest of the day once you end the technique.
Hornet's Nest Torment
Leap 10' high over your target's head and rain down blows with your polearm, striking 1d6+1 times and adding your HD to the damage dealt. Save if no attacks hit, on a failure you become unbalanced and fall prone on landing.
The Non-Present Cut
Do not think. One who strikes without thought may cut the face of God. Save - on a success, your strikes with a non-magical weapon ignore damage immunities and deal Heavy damage for 1d6+HD rounds. Strikes with magical weapons deal +1d6 damage. On a failure, you are unable to shake the useless hanger on of your conscious mind and take -4 to hit for 1d6+HD rounds.
Perfect Diamond Tower
Plant your feet firmly and inhale. For as long as you hold your breath, your AC is reduced by 6 and you cannot be moved by any force. You can hold your breath for a number of rounds equal to CON+HD. If you move or are struck, Save - you exhale on a failure.
Quickening the Way
Cut that which cannot be cut, using the edge of your sword to annihilate the distance between yourself and your target, travelling 50'/HD. For every 50’ travelled, there is a 1-in-6 chance of your blade shattering.
River of Blood
Impale yourself upon your sword and wrench it out: a torrent of boiling gore shall spring forth to mutilate your enemies. Roll HDd6 - deal this damage to all opponents within 240’, closest first, and suffer it in turn. Each enemy slain reduces the damage you suffer by 3. Using this technique while wounded is inevitably fatal.
Terrible Demonic Furnace
Ignite a fire within your soul and strike with your hands and feet. Unarmed strikes count as Heavy attacks and ignite struck targets per flaming oil. The fire burns safely within you for HD rounds, after which there is a 3-in-6 chance of it igniting your flesh. Whenever this power is used, you must eat triple rations when you rest - this is cumulative.
The Truth of War
Bare your warrior soul to your foes, that they may bathe in the past blood you have spilled. HD number of opponents with HD less than yours flee as soon as they are able. Targets with equal HD to you may Save to resist, with a -2 penalty for each foe you have slain during the encounter. This has no effect on opponents with higher HD than you - your inferiority is clear.
Arts of Cunning
Techniques of mobility, skill, and deftness.
Anti-Cat's Grace
You cannot fall from heights for HD turns. If you fall from a tightrope or board, you stand perfectly on the underside. If you step off a ledge, you flip back up to where you started. You can use this technique 9 times before you must make an offering to the Conclave of Cats.
Bright Tapestry
Your pupils dilate, drinking in and shining with all available light. You can see perfectly in the dark for HD turns, but anything brighter than a candle blinds you for 2d6 rounds.
Cultivation of Serenity
Meditate beneath the boughs of an ancient sacred tree. Feel its presence and graft a sliver of it on to your soul. You may embody this peace for 1 hour per day of uninterrupted meditation, becoming effectively unnoticeable and lifeless, yet still perceiving, while you remain unmoving. Further meditation must be undertaken to renew the graft.
Fishing the Veil
Take a silver hook, anointed in consecrated oils, and rest it within the skull of an anglerfish for a month. Cast at a spirit or phantasm, it draws them forth into the physical world for 2d6 rounds.
Hidden Grey Mantle
Step into a nearby shadow. It must be deep enough to envelop you whole. Step from another of similar size within eyeshot. The Things That Dwell In Darkness will permit you this trespass without demanding tribute a number of times/day equal to your HD.
Iron-Feathered Foot
Carve the glyph into the soles of your feet. Its counterpart is etched into a blade, spike, arrow, or similar. When the counterpart is lodged in a surface, you may treat it as if it exerts gravity on you and jump to it with no risk of harm. Jumping over long distances carries great force and may destroy the anchor on impact.
The Malleable Corpus
Through stretches, exercises, and diet, you can fit your body through any space no smaller than your head. Save when re-aligning yourself upon exit - on a failure you require a turn of rest or suffer -2 to all rolls.
Mindworm, Mindworm
Reach into the head of a sorcerer and pilfer a single spell. Treat your level as its Magic-User equivalent - holding and casting a spell of a higher level than you can handle requires a Save, with dire consequences for failure. You can hold a single spell at a time.
None So Blind
You cannot be perceived while you hold your eyes closed. Creatures will subconsciously move out of your way, if possible. You may snatch a glimpse for HD seconds without breaking the effect. The first time you end this technique, you are blinded in one eye. The second time, you are blinded in your remaining eye. Your sight returns when you rest.
Seventh Way Purification
Pierce the envenomed and diseased with a needle of bone whittled from a lion, and drain the rot as pure water.
Soft Embrace of the Earth
The ground will cushion your fall. You may plummet HD*10' without injury, as if landing on a stuffed mattress. Each time you use this technique, subtract 1HD from the next distance fallen until you rest beneath the earth.
You-That-Is-Not
Create a mirror within which lies 6 drops of your blood. Break it to summon forth You-That-Is-Not, which is bound to assist you with an immediate task - a battle, a trap, a puzzle, a logistical challenge, etc. Once the task is complete, You-That-Is-Not shall return from whence they came. The next time you create the mirror, if 6 drops of blood are used there is a 1-in-6 chance that You-That-Is-Not will remain once the task is done - they will seek to usurp you. This chance increases each time a mirror is made.
Further Thoughts
These all have a Fighter/Thief bent to them - Clerics and Magic-Users get flexible spells so I didn't want to infringe on that area, but there's nothing stopping those classes from learning any of these save weapons restrictions, if used.
The more powerful techniques generally have a trade-off, and they scale with the user's HD because spiritual cultivation or something. In line with Luke Gearing's post, these could provide HD in and of themselves as a form of 'supernatural' advancement. I'll be aiming to bring this together into a more coherent alter-advancement thing in due course.