The added weakness only applies to elemental damage, so basically this is most useful for tile damage. I would not use Norns on defense.
For offense that makes Norns a great hero though, particularly for those who play 3-2. She can essentially make, say your blue stack strong against a red tank + their green flank, or your green stack strong against the blue tank and red flank.
This hero is a lot like G. Chameleon with their own different applications.
Do you know how much Norns will be decreasing element defense?? I think this hero will be perfect hero for titans
She is great on offense! Having a medium speed 5* riposte hero is super useful. Add her other effects and she may be my favorite S3 hero. I admit to having level 23 mana troop, but a combo of Delilah, Sif and Norns beat a lot of really strong teams. I have done at least 50 raids with her.
Norns doesnāt actually decrease elemental defense like Falcon, Jackal, Evelyn, Frida, Arthur, and Panther ā she makes enemies weak against the element they are strong against.
So green heroes could do strong damage to red heroes, for instance, just like they would normally do to blue heroes.
Much like Guardian Chameleon, that could be useful on Titans, but would be a bit tricky to coordinate.
The big advantage over Chameleon is that the enemy also stays weak against their usual color.
Norns is definitely Offense oriented, not Titans or Defense.
But she/they (Norns is depicted as multiple figures) also require coordinating team building and attack approach ā definitely not a hero you can just toss on a team, fire, and forget.
Players who like planning their moves ahead and leveraging Tile damage will likely enjoy Norns a lot.
Players who like raw firepower and Special Skill damage probably will not.
Always will be somebody who like her but is not the hero what you must have other 5* is much better. Fenrir and Tyr is my favorite heroes of s3 also alfrike have amazing skill but she is to slowā¦
That depends on your roster. I believe you that Tyr and Fenrir will be better for you and many others. However, for me Sif is better than them and more useful than Alfrike. My yellows maxed are: Vivica costume, Drake, Delilah, Joon costume, Guin, Onatel, Inari, Gazelle, Poseidon, Rana, Neith, Musashi. I wonāt count Guin because she is used as war tank, and in that case Sif will be #3-#5 out of 12, behind only Delilah, Drake, and at times Gazelle and Poseidon.
That is if I get her; if the S3 odds are too bad this discussion will be moot.
Sorry if this was already asked butā¦ are all 18 heroes (except Fura) part of the Valhalla Summon portal?
So, it looks like:
4 heroes (1x3*, 1x4* and 2x5*)
4 heroes (1x3*, 1x4* and 2x5*)
4 heroes (1x3*, 1x4* and 2x5*)
3 heroes (1x3*, 1x4* and 1x5*)
3 heroes (1x3*, 1x4* and 1x5*)
5 heroes
5 heroes
8 heroes
Obviously they are not final and I didnāt play with any of them but IMO:
No, itās currently a subset of the heroes weāve seen so far ā and we know more are coming later that havenāt been in Beta yet.
Iāll be posting more details on the Valhalla Portal this week.
I suspect youāll think differently when you see some of the Heroes in practice. 
Beta is now closed, while a new Build is prepared.
Beta is expected to reopen later today or tomorrow for testing of the updated version.
Season 3 heroes have returned to beta. Here are the changes:
Alfrike
100%Realms
And before anyone asks ā yes, thereās a loooot of discussion and debate about Alfrikeās change, but Iām staying out of it until the end of this week when I have time to test 
As noted above by @DaveCozy, Beta has reopened, with balance changes to Heroes and several other updates.
The Season 3 Valhalla Summon Portal has also been updated with āfixedā Appearance Rates ā as such, Iāve now detailed it here:
Wow, that is some JF level nerfing 
Alfrike suffered a severe nerf. If it is changed to medium mana speed, it will remain viable; if not, I think it is unlikely that we will spend 6 tabards in very slow mana, with these reductions.
Also before anyone blames the beta testers for this change, it was completely un-asked for or suggested 
Completely out of the blue and has (as Dave said) created many many posts and feedback in a very short period of timeā¦
Hot damnā¦between this and Malosiās buff thereās a definitive shake-up in anticipated heroes now.
#waytogobetatesters
#notreallybetatestersareourfriends
#friendsfrenemiesenemieswhoreallyknows
#impeachguvnor