In Shining Force III you can build friendship bonus between two characters. Each type of characters give different bonuses. Main character Synbios gives attack bonus. Masqurin gives magic bonus. To build a friendship bonus between 2 characters. You have to attack the same enemy with both characters. There is 3 levels of friendship. While building friendship bonus is a pain to do and not worthwhile doing for most characters. Certain characters can build it quite easily like Masqurin and Noon with Spark 2 and 3. You get friendship points for each enemy you hit so using Spark 2 or 3 hitting multiple targets can boost the levels extremely fast. Also kill shots give more points. Best to check out the FAQ at GameFAQs to see all the different bonus.
It is also best to stick to one type of weapon throughout the game. Like Synbios can equip Sword, Rapier, Blade, and Dagger. You can get 3 levels of bonus per each type of weapon. As you level up the weapon type. The bonus you get is a new attack plus extra attack bonus for the type of weapon your using. Example say you have a Short Sword that gives 10 attack. Level 1 Sword bonus would give you a additional +4 attack. So equipping the Short Sword with a level 1 Sword bonus give you 10+4=14 dmg.
Character wise you should be able to figure out who to use depending on your playstyle. Most of the really good characters you get early in game like Dantares, Masqurin, and Grace. Just avoid using Penn as he sucks.
Forgot to mention Shining Force III Scenario 2 and 3 which was never released for the US or EU. You can get the English translation patch at Shining Force Central. It is well worth playing all 3 Scenarios or you will miss out on happens with the story from the other main characters party. Like at the beginning of Synbios's story. The first battle which is in the town of Saraband while your other main Character in Scenario 2 Medion is at Saraband Port for his first battle. Each of the main characters will encounter one another throughout each game. Also the dubbing is horrible. It's so bad some people actually enjoy listening to the bad voices. After playing the game so much. I'm immune to the effect of hearing "Now bear my Artic Blast!"
Finished Tear Ring Saga yesterday and started playing Shining Force III Scenario 3 again. Doing a normal difficulty gameplay with no egress. Usually play on hard difficulty but decided to play a non grinding playthrough for a change. The newest V14 patch is looking good. Also Donhort is one ugly mofo and I just got Rollie the Unicorn which is one of my favorite characters.