This is the lightning affinity: magic damage +6, magic accuracy +1, & casting time -14% path.
Trial 790:
Objective: Kill 50 treants in any weather.
Areas: See light-oriented staff common trials.
Trial 791
Objective: Kill 50 spiders in fire, wind, thunder, or light weather.
Areas: See light-oriented staff common trials.
Trial 816
Objective: Kill 50 mobs during thunder weather/day.
Areas: See light-oriented staff common trials..
Trial 817
Objective: Kill 75 beasts during thunder weather/day.
Areas: During Thundersday, Abyssea – Misareaux and kill Limestone Hare near Conflux #02. If you want to try your luck with weather, you can try Boyahda Tree on rabbits. There is also a Gigas’ Tiger camp in Vunkrel Inlet [S] with two BST Gigas near each other at (E-12).
Trial 822
Reward: [Lv. 75 Teiwaz] Lightning: Affinity +1
Objective: Apply the finishing blow to 150 vermin with at least 50 thunder damage.
Areas: Devegetator in Abyssea – Vunkrel near Conflux #05. Sauromongue [S] at (J-7) on Goblin’s Beetle. This area has two beetles very close to each other, so you can bounce back and forth between them. You could also try doing this on Chigoes off Mardis or Sheep if you have some help. Grauberg [S] has a sufficient supply of chigoes up all the time. One unresisted Thundaga III will kill four at a time.
Trial 823
Reward: [Lv. 75 Teiwaz] Lightning: MACC +1, MDMG +3
Objective: Apply the finishing blow to 200 slimes with at least 150 thunder damage.
Areas: Unfortunately, there are no slime camps in Abyssea. Den of Rancor near Hakutaku. To reach Hakutaku, you need to head towards H-13 on map 1 of Den of Rancor, which is the map immediately after the paintbrush of the souls door in the Temple. You will have to apply sneak to cross between tunnels, but there is a nice amount of slimes in each tunnel without any bat pops to worry about. I’ve heard that Bostaunieux Oubliette is a great place for this particular trial.
Trial 1682
Reward: [Lv. 75 Teiwaz] Lightning: MACC +1, MDMG +3
Objective: Apply the finishing blow to 200 beetles with at least 150 thunder damage.
Areas: Unfortunately, there are no beetle camps in Abyssea. Sauromongue [S] at (J-7) on Goblin’s Beetle again.
Trial 1683
Reward: [Lv. 80 Indra’s Staff] Lightning: MACC +1, MDMG +4
Objective: Apply the finishing blow to 250 funguars with at least 250 thunder damage.
Areas: Shadow Funguar in Abyssea – Konschtat near Conflux #04. Pasture Funguar or Cankercap both in Abyssea – La Theine both near Conflux #04. Speltercap in Abyssea – Vunkrel near Conflux #08, although Yaanei wanders in the camp for the funguars in this area. Grauberg [S] off Brasscaps. They are north of the campaign tower. These are much easier than the slimes since they have a lower maximum HP.
Trial 2182
Reward: [Lv. 85 Indra’s Staff +1] Lightning: MACC +1, MDMG +5
Objective: Apply the finishing blow to 250 treants with at least 250 thunder damage.
Areas: Rift Treant in Abyssea – Attohwa near Conflux #05. Barren Treant in Abyssea – Altepa near Conflux #05. Trotting Sapplings or Highland Treants in Abyssea – Konschtat near Conflux #02 and #07 respectively. Saplings and Treants both count for this trial like the earlier trial. Grauberg [S]’s treants are fairly seperated. The main benefit of this area for earlier trials is the weather. I am rather fond of the camp in Caedarva Mire at (G-9) on map #1.
Trial 2590
Reward: [Lv. 90 Indra’s Staff +2] Lightning: MACC +1, MDMG +5, Casting time -12%
Objective: Obtain 15 thunder geodes.
Trial 3023
Reward: [Lv. 95 Indra’s Staff +3] Lightning: MACC +1, MDMG +6, Casting time -12%
Objective: Obtain 40 thunder geodes.
Trial 3486
Reward: [Lv. 99 Apamajas I] Lightning: MACC+1, MDMG +6, Casting time -14%
Objective: Obtain 15 ramuites.
The Black Mage's Apprentice 