I did some testing and found some every interesting things about run JA's, All test were conducted with Shell V active, with enhancing skill at 221.
Wards - Run's wards work on both Magic spells and magic based tp moves, if you have the right rune up. Choose a element you want to defend against through RUNES and pick a ward and you'll have the type of damage mitigation you want. I test on birds in abbysea misareaux and Liement Ward completely absorbed bird tp move "Wing cutter" and restored HP, to do this I use liement ward and gelus runes.
Ward: Vallation - Is a ward that works on both magic spells and magic based tp moves. I tested this with 3 runes of the same element it appear to give a -50% damage reduction on magic spells and magic based tp moves. -50% magic reduction could be the hard cap. Its important to note that without the ward I was getting hit consistently for 144 dmg. However these are the results with the ward, Test log below:
1) Bird tp move "Wing Cutter" - dmg received 75
2) Bird tp move "Wing Cutter" dmg received 60
3) Bird tp move "Wing Cutter" dmg received 75
4) Bird tp move "Wing Cutter" dmg received 74
5) Bird tp move "Wing Cutter" dmg received 72
Ward: Pflug - not really sure maybe someone can test this
Ward: Valiance - I need to test this more to be sure but it appears to work the same way as ward: vallation but with a aoe group effect.
Ward: Liement - Absorbs magic spells and magic based tp moves that the runes provides resistance too. Tested this on birds in abbysea misareaux, "Wing Cutter" was the tp move i focused on. During the testing I had 3 Gelus runes (resistance to wind, deal ice damage) active at all times. Test log below
1) Bird tp move "Wing Cutter" - dmg absorbed 248
2) Bird tp move "Wing Cutter" - dmg absorbed 272
3) Bird tp move "Wing Cutter" - dmg absorbed 247
4) Bird tp move "Wing Cutter" - dmg absorbed 251
5) Bird tp move "Wing Cutter" - dmg absorbed 244
6) Bird tp move "Wing Cutter" - dmg absorbed 248
7) Bird tp move "Wing Cutter" - dmg absorbed 245
8) Bird tp move "Wing Cutter" - dmg absorbed 246
I found it interesting that wing cutter was hitting for around 145 damage +/- 5 whenever I didnt have Liement Ward active. Amount absorbed may go up based on how many runes of the same element are active.
One For All -this is a very powerful shield, it appears to nullify damage from magic spells and magic based tp moves, and its aoe to party members within range. Tested this on worms in Abyssea - La Theine and birds in Abyssea - Misareaux. While "One For All" was active along with 3 Flabras runes, Stone IV and Stonega III both hit for 0 damage. Moreover, also tested on birds in abyssea - Misareaux tp move "wing cutter" would also hit for 0 damage when "One for All" and three Gelus runes were active. Test log below:
1) Worm Cast "Stone IV" - dmg received 0
2) Worm Cast "Stonega III" -dmg received 0
3) Worm cast "Stonega III" - dmg received 0
4) Worm cast "Stone IV" - dmg received 0
5) Bird tp move "Wing Cutter" - dmg received 0
6) Bird tp move "Wing Cutter" - dmg received 0
7) Bird tp move "Wing Cutter" - dmg received 0
Elemental Sforzo - I tested Run 2hr ability, this ability nullifies magic and magic based tp moves. However with the 2hr active you don't need to have any runes up to block damage. Tested on worms in aby-La Theine and birds in aby-Misareaux, worms casting elemental magic the damage received was 0, and bird using tp move "Wing Cutter" also hit for 0 damage. Test log below:
1) Worms cast "Stonega III" - dmg received 0
2) Worm cast "Stone IV" - dmg received 0
3) Bird tp move "Wing Cutter" - dmg received 0
4) Bird tp move "Wing Cutter" - dmg received 0
5) Bird tp move "Wing Cutter" - dmg received 0
*Rune Enspell Damage seem to be linked to weapon delay and the base damage of the weapon. I changed my great sword from a galatyn with the base damage of 85 to an Etourdissante with the base dmg of 120, my enspell damage increased from 22-24 per hit to 36-40 per hit.