Oh well...
Ahriman's Lair, but the others weren't so hard.
Mt.Orion- with the scrolls was it very easy.
Lamp Land- There I had more problems because I didn't joined Lars a guild, wanted to make him time master, and I was in the Genie's Lamp before going to Thais.
Dreamland- the dream witches were the biggest problem,but I had 1 or 2 beast repellents

@Archoun
Eh I find the dream witches extremely easy since you can have Tei/John in your party I find the Rawvyn very hard tho, since Rhen & Lars/Elini are the only one who do the offense in magic...=/ (And plus Elini's spells cost too much mp!!!)

ahriman's lair, surely. its obviously harder than ahriman himself.

actually, i even went there not totally prepared, i didn't buy new supplies, since i knew i had a lot already.

imagine my surprise when i was near ahriman that almost my restorvatives were almost gone!!!

though, i am proud that i got to play the lair at about... level... 65 is rhen? she's the highest level in my team, followed by the others.

because of hardship, i think rhen even became level 71 before fighting ahriman. o_o yes, wow.

but at least i survived. found some techniques to be helpful. sleep flute did a great job in the end to defeat ahriman

The whole game is like a math formula - come to an area with the wrong approach, wrong spells, wrong armour, wrong character and it's the end. I think I did everything wrong at first.

The first time I dodged all the monsters up north and took the low level spells for Rhen and didn't realize I could take Lars to school too. I didn't realize which spells attacked a group, and which ones attacked only one character so Rhen somehow ended up with weak spells that didn't attack all four attackers. I died a hundred times in the Wildwoods, my worst area that I spent two days trying to get through. Now, I take at least one each of the level 15 spells (Holy Trinity, Thunderstorm) and it's over in one round even with Rhen and Lars at level 15.

It's not hard to get enough money for 20-30 lightning scrolls after Aveyond, and now Mt Orion is easier but I still get lost. I just didn't think to start relying on items before that section. The earth elementals were very hard to fight without the flood orb.

Beast Repellent is evil - I've gotten too far into an area that I couldn't fight my way out of when it wore off.

I thought Teijal was a weaker character because she could only take out one, but the way the game plays she can kill at least 25% of the attacking force in the first round. I didn't use her the first time.

Elini and Dameon were in my party in the Dreamland, and Lars was a necromancer. I got kicked hard. Elini doesn't fight as well as any of the other fighters, and she can't cast as well as the other mages so she's a bit mediocre at both. Having all magic users in the thieves hideout was a huge mistake.

Saving Lars to be a Time Master left me drowning in a number of areas - missed his fire power. The first Necromancer spell is a fire spell though, so the Flood Orb takes away the benefits of having him join a guild.

Galahad suddenly gets much tougher in Arhiman's Lair, and starts hitting for more than Teijal but he's very poor leading up to that fight.

I'm thinking of doing a more detailed walkthrough that gives the player the location of the most power for the characters. If I get the formula right for an area, it's over in two rounds at most. Haven't figured out how to take Arhiman in two rounds though...

my hardest moment was also in ahriman's lair, next is also dreamland. in ahriman's lair i saved after beating every enemy group (or angel of death). actually, i found the wyvern groups harder to beat than ahriman himself (of course i used dameon's sun fury on ahriman, so that was easy)

Like everyone else the hardest part for me was ahriman's lair,but when i first played the game mt. orion was pretty hard,but i only died like 4 times so i had a tad bit more luck.

The hardest:Ahrian's lair.
2nd: Dream World and Gennie Lamp
3rd: Dark Cave in blasted lands!
(belive me,i finished the game 4 times)

how i wish i could ever had finished the game , im on my first time thruogh aveyond 1, and im on the way to the second druid, as i am not on a really advanced part of the game i think the most difficult was mt oreon, because it was the longer part i ever played and it was not easy to know where to go, but as i allready knew about lightning scrolls i didnt die, and i also am really exaggerated, so i bought like 80 of them

Okay now that I've beaten the game 4 times I have a new top 5 hardest list.

1. Ahriman's Lair (easier with WitchDance,then Nightbird for Rhen)(Lars Decompose works good, but doesn't always go and only affects one monster so better to keep doing Lightning Storm though does less damage) (Ellini Red Demon though less effective) Tei'Jal doing attack and healing. I think at minimum a person should have their party members at level 70 to survive here. This last time I was at level 72 something like that and by the time I got to Ahriman I was level 76 I think and beat him in the first shot.

2. DreamWorld mainly cause of Agas and easy to get lost

3. LampLand

4. Demon Caves

5. Ice Caverns

Fighting Indra was the toughest for me.Second comes Ahriman and his lair.

My first time through the game I was obsesive about leveling up and buying armor, so I did pretty well at each new area. But I kept dying in Dreamland because I would forget to do something (grab a goodie, kill a bad guy, finish a quest, etc - that place was so confusing) and go back in . . . without getting more restoratives. Duh!

My hardest moment was crossing ahriman's Lair,i was level 79,they were so powerful , i had to bring like 50 casia's leaves and bring all kinds of refels,i hope there was aveyond 3.

now that i finished aveyond i can tell a better opinion, ahrimans lair was not really hard, i had the right level but the excitement makes it really hard, the only thing you want there is fighting ahriman.
demon caves were also hard, cause i thought meelee worked better there and went all the way through demon caves only wit my attack. LOL
lamp land was also hard but in all the game the part where i most died was in the rolling boulders from crypt maze.

I finished aveyond 1 once and im playing it again when im on ahrimans lair dameon is dead! And i dont have any casia leaves! LOL

Doesn't Lars have a Revive spell? Of course, you've got to have him in your active party

ya, i gotta say that lampland and the demon caves, also the dreamland are pretty hard. i haven't finnished the game yet but i hoping Ahrimans lair is hard, i love a good challenge. A good way to defeat lampland and demon caves is if you use song of madness, which rhen gets when the sword of choas is equiped and plague, which lars learns from the neromancer guild. And then have Tei'jal and Galahad attack. it works really well

1: Ahriman Lair{of course}
2: Dreamland {because, the witches}
3: Lamp land {It's so Long!}

My hardest moment was Ahriman's Lair and Ahriman himself. After I thought I could relax after killing a monster group... BAM A monster comes by and kills you. And it took me 1000000x just to defeat Ahriman.

And Mt. Orion, it took me at least a few hours just to find the ogre's lair.

well, never got a problem in ahriman's lair, i was not at a high level even, is it because i played build A or because i used sleep and berserking abilities continuously?

Perhaps it's both, since it's tough even at level 99 in Build B.