Not sure if this was mentionned before, but this unique accessory seems to have a hidden 10% physical damage boost, can't believe that i forgot to rob it from karl before starting new game+.

interesting. so the description means something beyond the +5 STR..... nice equipment to keep on a party member!
other accessories have similar descriptions that talk about stats but don't actually boost a visible stat... I wonder if the stats are just extra bonuses on top of the descriptions' bonuses?
Water Magic Ring: no visible stat bonus, Increases water magic atk. & magic def.
Wind Magic Ring: SPD +5, Increases speed and wind magic attack.
Earth Magic Ring: no visible stat bonus, Boosts physical def. & earth magic atk.
Thunder Magic Ring: no visible stat bonus, Increases accuracy & thunder magic atk.
Fire Magic Ring: STR +5, Increases strength and fire magic atk.

Water Amulet: no visible stat bonus Increases magic def. & water resistance.
Wind Amulet: SPD +5 Increases speed and wind resistance.
Thunder Amulet: no visible stat bonus Increases accuracy & thunder resistance.
Flame Amulet: STR +5 Increases strength and fire resistance.
Gold Emblme: MDF +10 Increases magic defense.

I was revising items and runes then test those with unclear descriptions (except those magic related stuffs which i think wont make a big deal). Strength sash and red loincloth are somehow useful but only a few characters could equip them. For the top tier list, after checking, i noted down that str sash is only available to Mizuki, Gau, Dario, Sigurd (even Lazlo can't equip it). Fortunately, Ornan is one of the few characters who could wear the loincloth.

I checked with a fire ring yesterday, it increases fire spell by 10%, not sure if those rings stack or not though, well if they do stack Jeane's thunder will hurt alot, A affinity plus another 30% boost and 10% magic boost from gear set and possibly alert status(1.5x???) too, wow, magic whoopass time, imagine heavenly thunder dealing 4.5k...

keep in mind, if you haven't already, that the fire ring may improve fire damage differently for people with different natural fire affinities. I would test it with like Katarina and Snowe, who are among the best and worst when it comes to natural fire affinity, and see if provides the same 10%.

doesn't matter who you choose for experiment, just have to make sure test objects are same character and same monster since my test only concerns comparision between that character's damage with and w/o the ring, it's not like the ring increase MGC stat or increase affinity level as in S3, it simply increases the damage after math. Just by coincidence, I picked both Katarina and Lo Hak for this test. Just now I got another pearl shell to make new ring, it's very cool to see that the rings do stack with each others.

I guess the fact that two stack to form 20% implies it's a uniform percentage change, but I would note that without that test, it was still entirely possible that it provided an affinity degree improvement, rather than a damage percentage, particularly since that's how magic rings work in both 3 and 5, although 4 is in lots of ways a black sheep compared to the rest of the series. It's also not like it was a particularly hard thing to test.