I tested everything on English SNES. The essential reasons for this guide are making Saradin a Sorcerer or Lich and showing more routing opportunity for evil endings.

Perks of Sorcerer and Lich besides 2 and 3 AoE attacks:

• Sorcerer notably gets Wizard's 2 ranged magic attacks in the front row and Lich gets 2 direct STR-based white attacks, unless he has equipment that overwrites the element.
• Lich has the best elemental resistances in the game and +1 AGI at level up compared to Wizard / Mage / Sorcerer. Note that PSX bug keeps Saradin at Mage resistances and Aisha/Norn with Shaman's.
• Sorcerer recruits Skeleton or Ghost and Lich recruits Wraith or Phantom anywhere. Not just at a town, anywhere they are on the map. Level 13 from when Saradin joins at level 15. Note that Galf comes with 2 level 17 Phantoms and 2 level 17 Werewolves.
• Recruited undead use: Fringe viability against Diablo since they dodge everything but Petrify and his white blade attack. Diablo's unit has Weak tactic, keeping the backrow safe for 1st round of combat with 2 undead in front. Else use to lower the average ALI in a liberating unit, if evil routing needs a bit more of a Reputation drop. Note that Norn uses Strong tactic so will heal versus kill undead and World protects against Jihad.

Also see alternate way to dump Reputation at Fogel's stage with the Dragon's Jewel.
I timed it to be 23 seconds slower than Borgnine trading on English SNES, just from the act of dumping 100 to 40. Diaspola is one of the slowest stages in the game and evil endings besides Devil do not need to clear it. Can go the Tristan path and avoid Mizal at Tundra.

Trade Sentoul Demon and Book of the Dead

• Famously, Borgnine in Anglem after clearing Diaspola wants to make a deal. Offers a measly 10,000 goth, then an Undead Staff (STAFF), then a Stone of Dragos for any Sentoul Demon (DEMON) you come across. If you refuse all 3 offers, you lose 5 Reputation points and this is repeatable to drop 100 to 0. No Reputation change for trading.
• In Sharom [Border] at the shop of Valna, Badista will forcibly trade an Undead Ring (UNDEAD) for a Book of the Dead (LEXICON), which he claims is buried somewhere on the continent. Surprise, there's 2 of them and they aren't buried. No Reputation change for trading.

Undead Staff

• Yushis' stage Antalia after clearing, visit the boss castle.
• Recruit Galf by defeating him at Antanjyl with 0 to 40 Reputation, 0 to 30 Alignment on the Opinion Leader and possessing Brunhild. Pops the question. Brunhild can be equipped or not, just have, but lose when recruiting. Also lose 15 Reputation and 25 Alignment (!) on Opinion Leader. After that, visit Powant N for an Undead Staff, Undead Ring and Blood Kiss (BLOOD)! No additional Reputation loss. Refusing Galf grants you +5 Reputation, +5 Alignment and Brunhild is kept.

Sentoul Demon

• Liberate Vyer in Pogrom Forest with 0 to 59 Reputation to get the Evil Censor. Trade it for a Sentoul Demon with Toad at Para. Both steps must be done before clearing the stage. No Reputation change for trading. Can still get the Quicksilver after clearing with 70+ Reputation, necessary for the best ending.
• Posha's sidequest on Diaspola, which must be done before clearing and for the best ending. Liberate Somyul with 45+ Reputation and, interestingly, Opinion Leader with 55+ Alignment. Agree for +3 Reputation. Can save a few seconds by paying 70,000 goth to buy the Beehive from the shop instead of taking the free one from the hidden temple. Revisit Somyu for the Sentoul Demon and +3 Reputation.
• Rauny's stage Valley of Kastro, visit Felgahnna after clearing in the top left section. Have 25-50 Reputation, inclusive, to be offered a question. Say Yes to the Thief to get a Sentoul Demon and lose 5 Reputation. Say No for no change and can revisit and answer again.
• Fort Allamoot, visit Killig Abal after clearing, which is the nearest city. Have 60-79 Reputation, inclusive, to get a Sentoul Demon. 80+ is a Black Lotus (LOTUS) that sells for 44500. No Reputation change.
• Fogel's Stage Shiguld / Ruined City, visit Mupan after clearing. No reputation change.
• Zeteginea the second to last stage, visit El' Keda after clearing. No reputation change.

Undead Ring

• See Undead Staff for recruiting Galf.
• Fogel's Stage Shiguld / Ruined City, liberate Dallu Sarram before clearing to get the Dragon's Jewel. No Reputation change. Don't sell it to Toad at the shop Kalishinpi. After clearing, return to Dallu Sarram and agree to trade it for an Undead Ring. If you refuse, you lose 3 Reputation and can repeat infinitely to drop 100 to 0. No Reputation change if you agree. If you sold it somehow, can buy it back at the shop for 150,000 goth after clearing.

Book the Dead

• Tristan's stage City of Malano, visit the boss castle after clearing. No reputation change.
• Slust's stage, Musplem, visit Segejin after clearing. No Reputation change.

RNG Manipulation

Completely defeating a non-boss unit, including a neutral encounter, has a 1 in 10 chance of dropping a consumable item. This is irrespective of LUK. Staff and Ring are among these 32 items but they're more like consolation prizes to Dream Crown for Princess or a Trade Ticket.