Planeswalker is more of an aptitude than a profession, which is why many Planeswalkers pursue a secondary power system, such as wizardry, psionics, bloodline sorcery, or martial arts. Ryan, without a doubt, has chosen to walk the path of the wizard to its very end.
This naturally brings up the issues of mana and magic. In Faerûn, most wizards are so-called "spell-slot" casters; they transcribe spells into their spellbooks and need only recite brief incantations to cast them. This saves time and avoids cumbersome casting processes, but the downside is that once a spell slot is expended, the spell must be re-prepared the following day.
Arcanists take a different path: they parse magic themselves. Instead of relying on the aid of the Weave, they use their formidable intellect to construct spell models and guide mana to cast spells. Consequently, they are not restricted by spell slots, but this requires an exceptionally high level of talent.
For a wizard traveling through the multiverse, the issue of connecting to the Source of Magic is inevitable—after all, there are places like Dead Magic Zones. Furthermore, magic is divided into many types: chaos magic, orthodox magic systems, elemental air magic, idealism-based magic, and so on. This is where Ryan's Planeswalker ability proves useful.
Someone suggested I could choose psionics as a backup, but psionics always feels a bit incompatible with wizardry. Perhaps I can expand the concept of mana in my setting: spiritual energy, magical energy, and elemental energy are all merely different forms of aether. How could mana be such an inconvenient thing!
The Weave is a monumental creation on the continent of Faerûn in the Forgotten Realms. While it allowed magical power to flourish, it also restricted the power of wizards—the influence of the "management" is evident there. Thus, in his early years, Ryan began using the System to learn how to parse spells himself, gradually teaching himself to cast spells independent of the Weave. His spell list is as follows: (As of Chapter 34)
0-Level (Cantrips)
Light—An oversized flashlight; essential for night travel and a top-tier tool for luring monsters.
Read Magic—Knowledge is power!
Mage Hand—Though it only has 5 pounds of force, it is truly convenient; a divine skill for the lazy.
Prestidigitation—Mom, look, I can do magic; I could perform on the Spring Festival Gala!
(There are too many 0-level spells, so I've only selected a few representative ones. Those interested can look up the complete D&D spell list.)
1st-Level
Sleep—Top-tier utility against both monsters and humans; who wouldn't want a hypnotic ability?
Magic Missile—Low damage, but maximum insult.
Grease—Crowd control is the golden rule. You ask about damage? Isn't the brute in the party there for that?
Alarm—Safety first, life above all. Master the art of "staying low," and you can travel all of Faerûn without fear.
2nd-Level
Rope Trick—A divine skill for team survival; you only have output if you stay alive. (For those of you with dirty minds, the one you're thinking of is Animate Rope; don't get them mixed up.)
Stone Shot—Who says my slingshot is no good? If you've got the guts, come try my stone bullet attack.
Darkvision—Surely no one needs to be told the importance of vision? If you aren't warding, you're a useless support.
3rd-Level
Fireball—Fireball is eternal!
Fly—Feeling stupid now? Grandpa can fly.
Dragon Skin—Triple Bloodthirst!
4th-Level
Dimension Door—Bring Blink, not Sprint, you filthy casual!
Wall of Fire—An essential tool for barbecues.
Regarding the Intelligence modifier, I am still learning. Emm, flipping through the D&D rulebooks is driving me insane. Forgive a data-obsessed perfectionist; I'm even mapping the world against the official 5e map just so you guys won't complain.
Ryan's Parsed Magic (Spells cast independent of the Weave—yes, those he can cast on his own):
Simplified Magic Missile—A simplified version of Magic Missile; reduced power, but significantly lowered casting difficulty.
Identify—Information is vital wealth; identifying magical items is a major source of income.
Tongues—To be in another world and unable to speak the language—what a despair that is.
Animate Dead (Level 1)—Actually, skeletons are quite aesthetic, aren't they?
Ray of Enfeeblement—Necromancy is actually quite useful, though the teachers don't like it. Sigh.
Feather Fall—Mom, I won't be afraid of heights anymore.
See Invisibility—I hate thieves, whether they are pirates or plagiarists.
Fly—Flight is one of humanity's greatest wishes.
Fireball—Explosion is art.
Dimension Door—On the importance of blinking.