DnD (3.5e or 5e)/Pathfinder Class/Level System/Add-on in Other Worlds

So just as the title says one of those Class and Level sytems in other Worlds. And there are already fair number, but each story with them seems incomplete in someway to me (or is either still ongoing or dropped/"Finished").

Now what I mean by this is mainly taking parts from others and mixing them to closer match/fit with Another World. Not unless stated otherwise the actual "Leveling Up" part where you would select your stuff will default to this method. On Space*attle (B where the * is) there is a Fanfic named [The Lord of the D20: Or How I became a Fighter in Middle Earth (3.5 D&D/LOTR SI)] by: KnightofTempest. And ITS Level Up mechanic is one I really like and as such will be using as default normally. Highly suggest checking it out its still ongoing and does regularly update so woot lol.

Now the mechanic to Level Up in that is the MC enters a Meditative State (Which is made to be easily done AFTER he has gotten enough exp to level.) in this state he mentally enters a room with a bookcase filled with books, each book is one Class he can choose for his next level. After selecting a Book it has all his info and choices for Leveling that Class and Level. Skills ranks follow the general listed Proficiency ie 5 ranks is Apprentice/Knowledgeable and so on, AND downloaded SOME actual knowledge Matrix style. With Feats and others being "Real World Skills" again Matrix style. At least these are how it is for the MC/Personal-Knowledge not the DM/Back-end side and such.

This room ALSO gains trophies from Major "Special/Story" Events/Enemies which again I REALLY like and will also being adding an extra that these would allow for gaining/selecting an additional feat, Spell of one level lower then current cast, or one extra skill point AND Hit Point. Three options to pick ONE of from. BUT that is only for DnD side. As for Pathfinder side these would/could instead be used to/for Mythic Levels/Tiers.

For such I will be referring to this as the Level Up Room or LUR for short.

Next the SI/OC would "Randomly" awaken already inside the LUR as themselves to select their 1st class with their equivalent stats and such or to fully make their character including selecting race/items/Etc that will all take effect after done with selection.

Now with that out of the way I'll now list and explain a few Worlds and ways could be added into. As well as a few recommendations that are DnD/Pathfinder in those Worlds too.

=================

Danmachi [Light Novel, Anime, Manga] (I know)

Recommendations: Space Battle| Media Shift (Danmachi/D&D 5e SI) by Mizuki_Stone

If a class like Wizard or such that CAN gain/learn new spells from Scrolls and such, then add Stand inside the LUR with a book and a bowl to the side of it. This book would have a list of all available Spells for that Class in this case Wizard, but would ONLY show those able to cast (Example a 3rd level Wizard can cast 2nd level spells so spells up to 2nd level would be listed but 3rd and higher would not be until being a 5th level Wizard and so on.), next to each is the price "purchase" them this cost would be Mana/Monster Stones/Cores for a scroll of that Spell at a ratio of 1 Stone/Core per Gold value per Monster equivalent level or higher for that Spell level (an example would be for a 1st level spell the Stone/Core MUST be from Monster that are equivalent to 1st level Adventurers but those from 2nd level monster would not work, if a scroll cost 25g then that is 25 1st level stones and so on, but for level 0 spells could use 1st level stones. For 2nd level spells you would need 2nd level stones. Now higher Stone can be used in place of lower ones for instance a 5th level stone would work the same 4th or lower stones for the same level spell of 4th or lower, but you couldn't get a 3rd level spell with 2rd of lower level stones.), but each of these can only be bought ONCE and then they no longer are listed.

The stones/cores must be on your person or within 5ft reach before Entering the LUR, afterwards they disappear and the scroll appears in hand or within reach for multiple scrolls.

All this would best fit if listed on Falna like in the Webnovel [Terrarian in the Dungeon by: Azazyel] in that it combines Skills, Class Abilities, and Special Abilities into one Skill.

Feats could either give equivalent Development Abilities (for a far more OP way), or included in the combined skill above (for a more sensible way)

Magic would be combine into One Magic/Spell Slot (Example Wizard's Spellbook, or Sorcerer's Spellbook). And could function normally following either Spells Per Day (More OP way.), or the Spell Point/Mana Variant (More sensible way.). Regardless these WOULD recive Enhancement from the Falna/Mind/Magic as well. One way I thought of that I like best is that it creates a separate "Pool" of Power (PP for short) that can be used as such, for every one letter Rank of Magic stat you get 1 PP this recharges following normal Danmachi "Mind" rules/Etc. These PP can be used at ANYTIME before casting a spell, but not after. PP has a Maximum of one Adventurer Level per use/increase. 1-PP can be used to increase a spells damage/healing amount by 1 per, 5-PP to increase a spells Distance Range by 1 (yes this can/would allow touch spells to become reach up to the amount used) foot per or increase a spells Save DC by 1 per, 10-PP to increase a spells Target Range by 1 per or to increase its targets amount by 1 per or increase a spells Penetration for overcoming spell Resistance by 1 per. 15-PP able to increase the Dice rolled by either one or change the Dice rolled up to one size larger per (Fireball maxes at 10d6 with this could go higher to 11d6/etc or change to 10d8) , 25-PP to apply a Known Metamagic Feat without increasing the Cast time but still increasing spell level/cost one Metamagic per (doesn't have to be a prepared Metamagic spell), and 50-PP to apply a Know Metamagic Feat without increasing cast time nor increasing spell level/cost able to do this for one Metamagic per (again doesn't have to be a prepared Metamagic spell, these function like the Sudden Metamagic Feats/Abilities).

Now DnD/Pathfinder level can either be separate/along-side (OP way.) or instead use Falna/Adventurer Levels in place for Leveling (more sensible way.)

Now for Pathfinder wither the Falna/Adventurer Level could work as/be Mythic Levels/Tiers is Pathfinder Levels separate (VERY OP way...), or Mythic Levels/Tiers are gained from doing Major/Special things (Like Leveling up in a month would count for ONLY 1 Mythic, Getting all S Rank Stats would again be only 1 Mythic, Soloing a Monter Rex at a lower level would be 1 Mythic. And so on but each of these can only be used/gained once each for that specific one, and could/should also have some that don't give Mythic after reaching higher levels or at least become more restricted/harder to gain... And yes something like having happy/caring/loving/etc S*X with Hestia would and SHOULD 100% count as a Mythic... cause I mean 10+ Millennia V-Card Goddess and she pick you? If that's NOT Mythic worthy then I don't want to know what would be... And yes in Fanfics and such that doesn't seem so most of the time but realistically should be a HUGE deal...)

Monster and Dice rolls/Etc would either be all DM/Back-end or something they can see similar to Dungeons and Dragons Online interface.

=================

Only I Am a Necromancer [Webnovel original, Manga/Manhwa], God and Devil World [Webnovel]

Either have it Separate/along-side or mixed-in being as both of those Worlds HAVE Class/Job Systems. So easiest would be just Make the Class/Job instead Be DnD/Pathfinder one, for G&DW this either happens at the start (OP way cause normally don't get Job until at level 10 at a village so would be a MAJOR boost compared to others), or don't get any Class levels until after 10th level (more sensible way.). Now for Separate/Along-side, Could still get 1st level Class but have to switch between what gets exp DnD/Pathfinder Class or G&DW System the best way for this is that it would be something like a mental Toggle that can takes focus to change (5-10mins) but can only be done once per day(long rest) this would help to not be THAT OP still OP but less so.

For Necromancer again best way and that fits almost scarily so is just have D&D/P Class take the place of 1st Class Card or have the Class Cards mainly/only be D&D/P Classes. In Necromancer after Leveling up you can pick ONE of either a Random Skill(Spell/etc), a Random Ability(Stat +1-3), a Random Item(fits class), a Random Others(never picked so idk), or a Rabdom Confirmed(A shown Random Skill/Item/Stats/etc like [Strength] instead of randomly being any stat.) With that Class Abilities/Spell/Etc would/should fall under Skill, Ability would still be Stats, Item would give a random Item based of Wealth by Level, Other would be a random Feat that qualify for, and Confirmed would be anyone of those but would shown WHAT it is before picking a level reward. For a more OP way could have it so Spells are not part of Skill so they are gained on level like normal, and only Class Features and Special Abilities are under Skill.

=================

Fate/Nasuverse [Anime, Light Novel, Video Game, Manga]

So just going to take the cop out and say it... D&D War Mage or Pathfinder MAGUS (Well Eldritch Scion FITS better but still a Magus)... Just use the LUR and D&D/P Class/Level System in place-of/with Magecraft/Mage Crest... Do I really need to say more?

=================

There are a LOT more but for now that's all I have listed for the rest/others those I will add sometime later no idea when though.