What is the highest level affected by the frenzy effect?

Solution 1:

One - Okay, WITHOUT bonuses at all, the Master level frenzy spell, Mayhem, will effect enemies up to level 25. The following perks add to that level limit in the following amounts:

Animage (+8 on ANIMALS) Kindred Mage (+10 on HUMANS Rage (+12 for frenzy spells)

So with those perks, the level cap increases on Mayhem from 25 to 45 on animals and 47 on humans.

Illusion Dual-Casting doesn't work for Master level spells since they require both hands to cast, but it does for single hand spells, so lemme do the math again for the best single hand frenzy spell, Frenzy.

At base level, frenzy effects enemies up to level 14. Dual casting APPROXIMATELY doubles this number (the doubling happens before perks are applied), this brings it up to 24, 12 gets added from rage, making it 36, which makes 44 or 46 depending on types of enemies.

Something of note, Animage unlocks at 20 illusion, Kindred Mage at 40, and rage at 70, so you wouldn't be gaining all the perk bonuses until at least 70 illusion.

Two - Your illusion perks won't effect your potions. As for highest level for a potion, that's a hard number to pin specifics on, as there are a lot of factors that can be manipulated as well as a general vagueness of information about the potion creation process.

THAT SAID, the fact that you can get the level cap up to the high 40s with just perks alone means that you won't need the best possible potions to make it that your spells can effect any non-immune enemy in the game.

Three - Dragons are always immune to illusion regardless of what you do. Undead(Dragrs, Vampires, etc), Daedra, and mechanical constructs (Steam Centurions, Worker Spiders, etc) are all immune until you take the Master of the Mind perk at 90 illusion.

Solution 2:

Just so you know, the adjustment when dual casting illusion spells occurs AFTER the perk adjustments, not before. So frenzy vs an animal affects a level (base is 14, +8 from animage, +12 from rage = 34: now multiply 34 by 2.2 for dual casting) 74 animal.

So yes, with full perks illusion spells can and do affect (if mob is not immune) all the mobs in the game.

Solution 3:

In addition to the bonuses mentioned, vampires also get a 25% boost to the power, which. when combined with perks and dual casting, raises the level to over 80. And speaking of vampirism, the Necromage perk, while a vampire, also increases the effectiveness of all of your active effects, increasing this boost even more. What does this mean? It means that you can increase the effective level of your Frenzy PAST the maximum player level.

Solution 4:

Over level 100.

Frenzy base level 14

Rage perk adds 12 levels bringing it up to 26

It's possible to create potions of Fortify Illusion that can boost your spells by 158%. I don't totally understand the math, but after taking one the numbers change in my magic menu from 26 to 48. If you dual cast, that's 2.2x effect (105.6 so level 105 not even counting Animage or Kindred Mage). If you are playing as a mage, focusing on both Enchanting and Alchemy can buff both Illusion and Destruction.

Level 1 vampirism and beyond buffs Illusion spells by 25%. Some of the highest level NPCs are Miraak and Arngeir, each with a max level of 150. There is little reason to frenzy Arngeir, and Miraak is already hostile. One fairly high level potential target is Gaius Maro in the Dark Brotherhood quest line. His level is your level up to 100. You can frenzy him so city guards kill him for you, letting you both avoid a bounty and earn your bonus.That can also let you avoid a murder on your in game stats if you care about that sort of thing.

There are some enemies that never stop leveling with you. These include random "race name here" encounters, mercenaries(if you provoke them) and magic anomalies, as well as some potential followers. The randoms and anomalies are already hostile, and the mercenaries can be made hostile by picking the right dialog option. Little reason to frenzy a follower unless you gave them some really good weapons and armor and want a bit of challenge. Simply hitting them several times will also make them hostile but could lead to a murder on your stats if you kill them.