There has been a lot of discussion on this page about how this weapon's skill, Thundercloud Form, interacts with various spells, talismans, and great runes. I have done some testing and will post both my conclusions and some raw data below. It is important to remember that these tests are far from conclusive and I would appreciate further testing and validation from others. In particular, Thundercloud Form returns inconsistent damage numbers between tests. This occurs even when the conditions appear to be unchanged between tests. If anyone can explain why this is happening, it would be of great benefit to the community.
Setup:
* Dragon King's Cragblade +0 (152 physical AR / 90 lightning AR)
* 18 STR / 75 DEX
* no other weapons, armour, talismans, or spell effects
Notes:
* Enemies in rain take increased lightning damage (10%)
* Enemies in water take increased lightning damage (10%)
* Enemies who haven't noticed you take increased damage (??%)
* Stance-broken enemies take increased damage (??%)
Testing vs the first Giant Land Squirt encountered from The Ravine site of grace:
* L2 tap = 512, 346, 400, 346, 346, 401
* L2 fully charged = 775, 527, 778, 527, 775, 894, 527, 775
Q: Does the Shard of Alexander increase the damage of Thundercloud Form?
A: Yes.
Q: Does the Godfrey Icon increase the damage of a fully-charged Thundercloud Form?
A: No
Q: Does the Lightning-Shrouding Cracked Tear increase the Damage of Thundercloud Form?
A: Yes (659, 970, 970, 851, 970, 851)
Q: Does Flame, Grant Me Strength increase the Damage of Thundercloud Form?
A: No (580, 675, 675, 775, 710)
Q: Does Thundercloud Form stack the Rotten Winged Sword Insignia, Millicent's Prosthesis, or the Thorny Cracked Tear?
A: No
After running these tests I moved to the Prayer Room site of Grace in Elphael, Brace of the Haligtree. Testing vs the nearby Cleanrot Knight resulted in the following damage numbers for a fully-charged L2: 439, 521, 435, 439, 443, 443, 443, 443, 527
Q: Does Thundercloud Form benefit from the Spear Talisman?
A: No (519, 443, 438, 435, 443, 431)
Q: Does Thundercloud Form benefit from the Lightning-Shrouding Cracked Tear?
A: Yes (476, 499, 469, 472, 479, 494, 472)
Q: Does Thundercloud Form benefit from Flame, Grant Me Strength?
A: No (478, 588, 443, 435, 443)
Q: Does Thundercloud Form stack Malenia's Great Rune?
A: Yes (each tick of damage from the lightning cloud restores about 10% of your missing health)
A few more thoughts:
I really have no idea why Thundercloud Form returns such inconsistent damage numbers. It is possible to strike anywhere between one and seven times with the thundercloud itself before materialising and slamming to the ground for the final (significantly more powerful) strike. I tried to initiate all Thundercloud Forms from point blank range and rarely had less than six ticks of damage before the final strike. The test results that I find to be the least conclusive are those around the Spear Talisman and the LSCT / FGMS. I am not sure that I managed to land the final strike during an enemy's attack animation a single time. The small ticks of damage from the Thundercloud Form were so effective at stun-locking the Cleanrot Knight that they were never able to attack during the final strike. I tested the LSCT and FGMS because I wanted to work out what percentage of Thundercloud Form was physical damage and what percentage was lightning damage. I am leaning towards the opinion that this skill deals 100% lightning damage but am not certain whether it scales with the lightning portion of the weapon's AR or the physical and lightning parts combined.
I hope this helps to answer a few of the questions that people may have about this skill. I would love it if someone else could do some more testing and post their results.
