I don't want either. I want Immortals rules.
Honestly, I'm not fond of prestige classes because they force you to plan your character out in a very specific way.
Here's an example of one of the ten prestige classes in
Adventures in ZEITGEIST. Each of them is just three levels, and is linked to one of the 'character themes' that highlight ongoing social trends in the setting. The hope is that they don't require you to distort your character creation at all.
Applied Astronomist
The myriad motes shining in the night sky influence the world through subtle magic, and with the proper study that magic can be grasped and harnessed. Skyseers, familiar with sensing the patterns of the stars, can learn to wield this magic in battle, enhancing themselves, conjuring otherworldly destructive forces, or shifting the environment to be more like those of these wandering planes.
Prerequisite: Skyseer Vision feat, proficient in Arcana and Nature, character level 7th, must be able to name and identify all the planets detailed in Chapter Five
Features
Hit Dice: 1d6 per applied astronomist level.
Hit Points: 1d6 (or 4) + your Constitution modifier per applied astronomist level.
Spellcasting. Add the following spells to all of your classes’ spell lists:
augury, clairvoyance, contact other plane, divination, guidance, guiding bolt. Whenever you gain a level in this class, it grants or advances your choice of bard, cleric, druid, sorcerer, or wizard spellcasting, or warlock Pact Magic and Mystic Arcanum. This advancement includes spell slots, spells prepared, and spells known.
Stargazer (1st level). You gain darkvision with a range of 60 feet, or if you already have darkvision, its range is extended by 60 feet. The range increases to one mile under starlight or moonlight. You cannot be blinded.
Touching the Wheel of Heaven (1st level). Different planes are in ascendance or decline each day, entering or leaving conjunction with various constellations and other celestial phenomena.
After a long rest, if you were able to spend an hour watching the night sky in the past day, roll two times on the following table to determine which planes you are able to connect to. Reroll duplicates. This connection determines the effects of some of your powers. The connection lasts until you take another extended rest, but no more than 24 hours.
Table: Planar Connections
1d8: Roll two times each day.
1 – Jiese, plane of fire.
2 – Caeloon, plane of air.
3 – Av, plane of dreams.
4 – Ostea, plane of water.
5 – Urim, plane of earth.
6 – Mavisha, plane of journeys.
7 – Ascetia, plane of time.
8 – Amrou, plane of wards.
Heavenly Flare (1st level). As an action, you can choose one plane you are attuned to and one creature you can see within 60 feet. You manifest a flare of starlight which deals 2d6 radiant damage to that creature and inflicts an additional effect based on the plane you chose. The damage increases to 3d6 if your character level is 11 or higher, and 4d6 at level 17 or higher. A saving throw against your spell DC negates the damage and extra effect. The type of saving throw depends on which plane you choose.
{Table won't format well. Here's an excerpt:}
* Jiese: (Dex save) The target catches on fire. A creature that is on fire take 1d10 fire damage at the end of each of its turns until it spends an action to put itself out. The damage increases 2d10 when you reach 17th level.
* Caeloon: (Dex save) Erratic winds impose disadvantage on the target’s attack rolls until the end of your next turn.
* Av: (Wis save) The target is charmed until the end of your next turn.
* Ostea: (Con save) If the target has blood, choose a creature within 60 feet of you to heal an amount equal to the damage you dealt.
{there are four more options}
Follow Yonder Star (2nd level). You can let the stars guide your movement and protect you. At the start of your turn you can call upon the stars. This does not require an action. Until the end of your next turn your enemies miss with their opportunity attacks that target you or your allies. You cannot use this power again until you take a long rest.
Space Travel (2nd level). Each day you gain movement options or bonuses from the two planes you are connected to.
{again, table wouldn't copy-paste, so here's a sampling}
* Urim: You ignore the first 5 ft. of forced movement whenever you’d be moved. You may automatically resist being teleported or knocked prone.
* Mavisha: You can teleport 30 feet as an action. If you arrive in an area that provides concealment or that no other creature is observing, you can Hide without spending an action.
* Ascetia: If you did not move on your previous turn, double your speed.
* Amrou: Enemies treat the ground within 10 feet of you as difficult terrain.
Cataclysmic Conjunction (3rd level). As an action you can cause a portion of another plane to temporarily merge with reality. Choose a plane you’re attuned to today. A 15-foot-radius burst within 60 feet of you becomes suffused with the essence of that plane.
When you use this ability, creatures in the burst must make a save against your spell DC. The chosen plane determines the type of save, as with
heavenly flare. On a failed save, a creature takes 4d6 force damage and 4d6 radiant damage and suffers the same effect as a
heavenly flare of that plane. A creature that succeeds its save takes half as much damage and suffers no extra effect.
For the next five minutes, that area is altered, depending on what plane you chose. You cannot use this power again until you take a long rest.
{table formatting, yadda yadda}
* Caeloon: Area fills with your choice of fog (concealment), or winds up to 30 miles per hour (disadvantage to ranged weapon attacks at short range, and long range attacks are impossible), or calm air (makes the temperature comfortable and the air breathable).
* Ostea: Area fills with blood to the depth of your choice, either calm or choppy – which requires a DC 5 or DC 15 Strength (Athletics) check.
* Mavisha: When a creature enters the area, you can spend your reaction to have it arrive in any space along the interior perimeter of the area. When a creature leaves the area, you can spend a reaction to have it exit on any exterior space along the perimeter.
* Amrou: Creatures in the area lose resistances to damage, and if they are immune to a damage type instead they have resistance to it.
