Cap'n K's notes.
For all the characters, I have listed three sets of stats. "High" is very close to maximum stats for a character. I'm sure I missed a few items, but that's with mastering at least 95% of the items in the game. "Ave" is what a typical first playthrough looks like, with many items not found. "Fix" is the fixed stats found in the Bonus Chapter. These are quite different from what a character looks like in actual gameplay, so I'm disregarding them and only listing them for completeness.
Strength affects how much damage you do with physical attacks, and reduces physical damage you take. Magic affects how much damage you do with magical attacks, and reduces how much magical damage you take. Agility reduces the amount of clockticks you have to wait until you can act again (think FFT Speed stat). Vitality is a form of defense, reducing damage you take (in combination with strength and magic). Some attacks ignore Vit, which would be comparable to ITD in other games (but these attacks do not ignore strength and magic!).
Characters in Riviera do not gain levels. Instead, they gain stats every time they master a weapon. By using a weapon a certain number of times, they will gain a sizeable amount of HP, some strength or magic, and 1 point of vitality. Agility is only able to be raised by finding a Mana Wisp in a level, which raises all your stats.
Characters have an Overdrive gauge, which is similar to a limit break. It always starts at zero at the beginning of a fight. The gauge will fill every time they damage the enemy, and every time the enemy damages them. Multi-hit attacks will fill the gauge faster than single-hit attacks. Depending on the weapon type, a character can use their Overdrive move when it is 1, 2, or 3 levels full. Ein only has an Exlevel Overdrive which can be used at any level of Overdrive (the higher the gauge the more hits it does). Once this attack is used, the Overdrive gauge shatters and no more Overdrives can be used in this match.
One other note about the difference between Avoid and Guard. This is similar to Valkyrie Profile, where an enemy can dodge an attack or parry it. A weapon that says XAvoid will always hit the target, but can still be blocked. A weapon that says XGuard can not be blocked, but it can whiff. XAvoid+Guard will always damage the target.
There are several elements in Riviera, and characters have built-in resistance or weakness to them (there's no armor or accessories in this game). I've listed thier weaknesses (slight<poor<bad<horrible) and resistances (slight<decent<good<great).
Ein
High: HP 1315/Str 122/Mgc 60/Agl 20/Vit 61
Ave: HP 1105/Str 101/Mgc 51/Agl 16/Vit 51
Fix: HP 1000/Str 85/Mgc 27/Agl 10/Vit 75
Ein has slight resistance to physical attacks, good resistance to Dark attacks, and slight weakness to Fire, Ice, and Lightning.
Typical endgame weapons:
Einherjar (Slash - 1 hit of 224 holy physical, XAvoid)///Disaresta (Exl OD - 8 hits of 220 holy physical)
Gran Sabre (Slash - 2 hits of 167 holy physical)///Divine Ascension (lvl 3 OD - 8 hits of 178 nonelemental physical)
Rosier (Stab - 3 hits of 116 holy physical - low accuracy)///Terre Promise (lvl 2 OD - 6 hits of 163 holy physical damage)
Infinite Arc (Mow - 1 hit of 211 ice physical)///Rainbow Flash (lvl 1 OD - 1 hit of nonelemental physical - low accuracy, XGuard)
Southern Cross (Strike - 2 hits of 140 nonelemental physical)///Burn Bullet (lvl 1 OD - 4 hits of 151 fire magical)
Diana's Bow (Shoot - 1 hit of 235 lightning physical)///Glint Arrow (lvl 1 OD - 1 hit of 415 lightning physical)
Comments: Solid main character. If you're weak to holy damage you lose to him.
Cierra
High: HP 1525/Str 37/Mgc 156/Agl 10/Vit 63
Ave: HP 1280/Str 27/Mgc 137/Agl 8/Vit 52
Fix: HP 1000/Str 27/Mgc 85/Agl 5/Vit 75
Cierra has slight weakness to physical attacks, bad weakness to Ice, and great resistance to Fire.
Typical endgame weapons:
Southern Cross (Magical Shot - 2 hits of 167 fire magical)///Calamity Flare (lvl 3 OD - 8 hits of 194 fire magical)
Viper Whip (Whip - 3 hits of 105 nonelemental physical)///Snake Bite (lvl 2 OD - 6 hits of 119 fire physical - ignores target Vit, does double damage to beasts)
Gran Sabre (Magic Blade - 2 hits of 154 nonelemental magical - low accuracy)///Hyper Blade (lvl 1 OD - 3 hits of 189 nonelemental magical)
Rosier (Magic Shot - 3 hits of 119 holy magical - won't hit flying enemies)///Holy Blight (lvl 1 OD - 4 hits of 148 holy magical)
Diana's Bow (Try and Shoot - 1 hit of 222 lightning physical - low accuracy)///Plasma Shot (lvl 1 OD - 3 hits of 199 lightning magical)
Comments: Tanky mage? Huge HP and magic give her durability and offense. But she is terribly slow.
Serene
High: HP 1265/Str 142/Mgc 63/Agl 20/Vit 59
Ave: HP 925/Str 109/Mgc 49/Agl 18/Vit 45
Fix: HP 1000/Str 70/Mgc 42/Agl 15/Vit 75
Serene has slight weakness to physical attacks, poor weakness to Fire, bad weakness to Lightning, good resistance to Ice, and slight resistance to Dark.
Typical endgame weapons:
Infinite Arc (Reap - 1 hit of 261 ice physical - XAvoid)///Serene Absolute (lvl 3 OD - 8 hits of 163 ice physical)
Leyte Claw (Scratch - 3 hits of 101 lightning physical)///No Mercy (lvl 2 OD - 5 hits of 154 lightning physical - gets stronger as Serene's HP get lower)
Gran Sabre (Mage Slash - 2 hits of 151 nonelemental magical)///Sonic Spear (lvl 1 OD - 4 hits of 147 nonelemental magical)
Rosier (Stab - 3 hits of 125 holy physical)///Judgment (lvl 1 OD - 1 hit of 429 holy physical - low accuracy)
Viper Whip (Swing - 3 hits of 85 nonelemental physical)///Detonator (lvl 1 OD - 3 hits of 165 fire magical - low accuracy, XGuard)
Comments: Looks slightly better than Ein on paper, but she's not that useful ingame. Several weaknesses counteract her otherwise decent durability.
Lina
High: HP 1190/Str 105/Mgc 96/Agl 30/Vit 57
Ave: HP 965/Str 84/Mgc 79/Agl 28/Vit 45
Fix: HP 1000/Str 56/Mgc 56/Agl 25/Vit 75
Lina has slight weakness to physical attacks, bad weakness to Fire, and good resistance to Lightning.
Typical endgame weapons:
Diana's Bow (Shoot - 1 hit of 277 lightning physical)///Stardust (lvl 3 OD - 8 hits of 194 lightning physical - does double damage to flying enemies)
Leyte Claw (Scratch - 3 hits of 105 lightning physical)///Rising Claw (lvl 2 OD - 6 hits of 142 lightning physical - gets stronger as Lina's HP get lower)
Infinite Arc (Swing Around - 1 hit of 206 ice magical)///Misty Arc (lvl 1 OD - 1 hit of 361 ice magical - low accuracy, XAvoid)
Viper Whip (Swing - 3 hits of 93 nonelemental physical)///Constrictor (lvl 1 OD - 3 hits of 151 nonelemental physical - gets stronger as Lina's HP get lower, damages Lina proportional to damage done)
Comments: Super fast, and almost equally good at physical or magical. A little too dependant on lightning elemental though.
Fia
High: HP 1320/Str 82/Mgc 129/Agl 25/Vit 56
Ave: HP 1100/Str 57/Mgc 117/Agl 23/Vit 47
Fix: HP 1000/Str 45/Mgc 67/Agl 20/Vit 75
Fia has bad weakness to Dark, and slight resistance to Fire, Ice, and Lightning.
Rosier (Touche - 3 hits of 95 holy physical - ignore target Vit)///Cadenza (lvl 3 OD - 8 hits of 183 holy physical - XGuard)
Southern Cross (Healing - recovers 55% of max HP)///Magenta Missile (lvl 2 OD - 6 hits of fire magical - won't hit flying enemies)
Diana's Bow (Shoot - 1 hit of 254 lightning physical)///Radiant Arrow (lvl 2 OD - 4 hits of 208 lightning physical - double damage to flying enemies)
Gran Sabre (Slash Upward - 2 hits of 145 nonelemental physical)///Riot Edge (lvl 1 OD - 4 hits of 151 nonelemental magical - won't hit flying enemies)
Comments: 55% Healing? Yes please. Her offense is semi-questionable, as she doesn't really utilize her high magic stat well. But when you can heal that much you can take your time killing your enemy.
Not listed for weapons: Books (lvl 2 OD for Cierra, lvl 1 for Lina and Fia), Spears (lvl 2 OD for Ein and Serene, lvl 1 for Lina and Fia). I didn't have any good examples of these on my savefiles. I also didn't list limited use items like Ein's Fanelia(8 hits of fixed 999 damage) or Fia's throwing daggers (Kiku-Ichimonji, 8 hits of 120 nonelemental physical, ignores target Vit, does more damage as Fia's HP get lower). These are just way too powerful, and you don't get to use them that much ingame.
HP: Cierra > Ein > Fia > Serene > Lina
Str: Serene > Ein > Lina > Fia > Cierra
Mgc: Cierra > Fia > Lina > Ein > Serene
Agl: Lina > Fia > Ein=Serene > Cierra
Vit: Cierra > Ein > Fia > Lina=Serene
