Heroes 5.5 WarGame Edition - Tactical Edition.

I'm curious about the Elven ritual. Is it actually possible to do something like that?

I really hope it can be done, and specifically in that form. Mostovik said it was possible.
By analogy, the dark ritual will also cost only 25% of a turn.

Land Master already influenced crystals and swords, it just wasn't in the description. As for the earthquake - there is also the "Earthquake" ability that deals damage.

Earthquake (the ability) is an extremely situational perk and was therefore removed, while the earthquake spell is granted via "Land Master".

Please note that a number of spells cannot be obtained in the guild, only through perks: Earthquake, Summon Elementals, Divine Retribution, Regeneration, Frostbite, Wall of Fire, Sorrow, Vampirism.

Thus, Earthquake will never clutter the guild layout anymore :)

In general, here is the list of perks that were removed:
- Reflection (too low resistance)
- Resistance (replaced by improved Fire-resistant Armor; and Call of Darkness - manticore will be based on it)
- Grave Cold (negligible damage)
- Patronage of Ashi (potential dummy perk for new perks)
- Trophies (weak and uninteresting)
- Traveler's Luck (weak and uninteresting)
- Navigation (extremely situational; by setting the options to 0, a dummy perk for new perks can be obtained)
- Barbarian Luck (Barbarians already have fine magic protection in transformations, no need to add extra resistance; and Pack Leader - wolves will be based on it)
- Ground Shake (extremely situational, only for sieges; by setting the options to 0, a dummy perk for implementing new perks can be obtained)
- Death's Tread (extremely situational, only for sieges; and a perk of the same name with Lunar Templars will be based on it)
- Exploding Corpses (extremely useless)
- Magic Exhaustion (a worse version of Undead Magic Protection, as it only affects hero spells)
- Banishment (extremely situational perk, since Elemental Balance already exists)
- Exorcism (extremely situational perk, since Elemental Balance already exists; by setting the options to 0, a dummy perk for implementing new perks can be obtained)
- Return to Void (extremely situational perk, since the summoning nerfs in Summoning Transformation are sufficient)
- Harbinger of Death (no need to duplicate the corresponding building in the Necropolis)

Added after 4 minutes

It's possible... Or you could check if the amulet is equipped. There might not be a script function to check for an artifact, though... But I think there was a function to check for an equipped artifact set.
Sigh, I've forgotten scripts.

Check and reset the ultimate if the hero doesn't have the amulet? That option won't work, because Academy and League heroes receive one-time bonuses like all spells (which cannot be forgotten) and +100 mana and Spell Power.

Added after 9 hours 4 minutes

There's hardly any mana in this mod

I can say that 5 mana per unit of knowledge is an ideal solution for finals; no problems with excess mana or knowledge becoming irrelevant.

On the other hand, I haven't played much on the map with my mod yet. It's possible that mana regen will be increased from 20% to 40% (60% with mysticism) per day, meaning essentially 1 knowledge will restore 2 mana - which is twice as high as in the original. Theoretically, this solution is almost obvious: why should a player spend 5 times less mana on a breakthrough battle than on a final battle? Since the goal was to make knowledge desirable, rather than forcing the player to cast only 1-2 times per battle (breakthrough). In my opinion, this solution is stronger and better than the classic 10-fold limit, which makes the mage too dependent on wells and leaves tons of unused mana in the finals.