Considering the recent obscura kick... today's topic is "characters who are not actually obscure but still not getting ranked in the DL any time soon." In this case, characters also in Smash Brothers, except fighting by DL rules. Without further ado, our contestants...
Mario - Hey, he's got a perfectly legal ranked form, at least, in Mario RPG. (And Paper Mario, I guess.)
Ike - We like Ike! We like Ike! (As above, but FE9/10.) Yay for two sanity checks.
Link - Zelda II form is actually moderately legal, if still a solo-RPG-sortof. Link's got a cruddy ranged attack at full health, a shield for blocking ranged attacks, hits flying enemies with upstab, and can bounce on people's heads for great justice with downstab. Link's got 8 magic, er, "boxes..." let's call it MP. Shield halves damage (1 MP), Life heals 3/8 of his health for a wee bit more than 3 MP, Reflect might allow Link to reflect certain types of magic with his shield (1 MP), Thunder is excellent damage to the screen (4MP). Less useful magic includes Fire, which gives Link a fire-elemental long range attack for when he cares, which is rare; Jump doesn't translate very well to the DL aside from forcing Valvalis out of spin in combination with a downthrust; Fairy flies but can't attack and is only useful for owning Laguz / Phantom Brave Ash; Spell... is a transformation spell that's probably illegal due to reducing the XP award to worthlessness, but maybe not, YRMV.
One quirk I'm not certain everyone respects: It takes very little time for Link to cast spells - the game pauses, and it doesn't really slow him down from attacking all that much. So Link doesn't really get "heal-locked", and Link can instantly open with Shield and also start attacking turn 1 with not much delay (maybe go from average to slightly-below average speed for that first attack) - to me at least.
Samus - Okay, now we're getting deeper into the interpretation swamp. I'm using Super Metroid as a base, as most later Metroids have copied her abilities there to some extent. She can charge shots for her best damage. Her beam weapon is optionally ice elemental when she wants it to be, and is pretty hard to dodge. Wave Beam goes through walls and enemies, so you could argue it's ITD? It does offer a damage boost in game, but meh. She's also got a flurry of Super Missiles, though by endgame they do the same as a Plasma/Wave/Ice beam. Maybe they fire faster, but are less accurate due to less spread? It's not very important. Most importantly, she can play Xorn-lite and stack up future damage by dropping a Super Bomb then charging a shot, allowing her to release a bunch of damage at once to screw with healers.
Defensively, the Varia suit protects her from harsh environments (Uh... Pokemon weather? Not real common in the DL). She's got 4 Reserve Tanks, which may or may not be "included" as part of her base HP... she has 100% PCHP with a 20% reserve if you see it as a bonus, or 84% normal PCHP with a 16% reserve if you force her to have average HP (might matter for gravity attacks based off max HP?). More importantly, the Varia suit halves damage and the Gravity suit quarters it. Does this "count", or is it scaled away as the Gravity suit = assumed armor = average defense? People seem willing to give Zack credit for auto-Protect/Shell off armor, but nobody suggests DW1 hero is a tank due to Erdick's Armor, so you figure it out. If you read the Nintendo Power "Classified Information," then you'd know that Samus also has an emergency full healing move that comes at the cost of a mere 10 of each Missile/Super Missile/Power Bomb. It does not refill the reserve, however, and Samus has to be at death's door to use it. Not a problem to set up in-game, but like FF8 limits much harder in the DL.
If you don't scale away the Gravity suit, she is freakishly durable against attacks that aren't ITD making her a great slugfester. As she can take a hell of a lot of punishment in both Smash and the Metroid games, I'm inclined to give her some defense respect in a holistic nod. On the other hand, she doesn't exactly maneuver easily, so I'd definitely see her as slow and unevasive, too.
And if you use other forms? Have a blast.
Snake - Hey, he was ranked in the RPGP! Uh... Snake doesn't really have a legal RPG form. You figure out what to do with him, as translating sneaking to the DL is hard.
The most I'll say is that while hidden, Snake's probably vaguely like Belial; you need a mass MT effect to hit him and can't target him individually. That or some kind of detection spell a la BG2 True Seeing. CQC is basically instant death (and would be resisted by ID blocking), and if hidden a sniper rifle probably powers up damage the longer Snake aims it to a maximum of 3 rounds. Or something. I'm just making stuff up here. (Under this version, ID-immune buffers would give him problems while he waits in hiding, as do people with MT damage.)
Pikachu, Jigglypuff - Cheer on from the sidelines, as the above combatants are mostly some shade of Heavy (at least in some interpretations?), and they're not.
Marth and Roy; Bowser and Peach - Feel free to vote on these two vs. the field as well if you know 'em, just figured Ike was a good base representative and didn't want to flood the field with Fire Emblem. Same deal with Mario and SMRPG.
Sonic the Hedgehog - got all of one person voting in his match in Futurama: Anthology of Interest, so didn't bother listing him, but if you are that one person (OK), feel free to toss him into the Brawl. Also every gentleman of class hates and despises the spiky blue would-be usurper of the plumber's crown anyway, so his shunning should not be a surprise.
Mario (Mario series) vs. Ike (FE:Radiance)
Mario vs. Link (Zelda 2)
Mario vs. Samus (Super Metroid)
Mario vs. A Harmless Box (MGS series)
Ike vs. Link
Ike vs. Samus
Ike vs. Box
Link vs. Samus
Link vs. Box
Samus vs. Box
-Special actually-ranked Godlike* bonus match-
"Demoted from Godlike" Ness (EB) vs. "Demoted from Brawl" Mewtwo (PKMN)
*Ness Godlike in spirit if not in fact?
Feel free to vote according to whatever interpretations strike your fancy.