I have attempted to play several Famous + White Magic (for Just Cause) builds and with 20 fame early game, I still get basically zero hero recruits all the way through researching Summon Hero.

First question: have you been keeping enough gold in your treasury to hire them? For example, if you've been floating less than 100 gold, no one will show up.

Second question: which version are you playing?

Yes, I have been floating 100g

Version 6.01

Here's a wiki page covering the mechanics for the base game (v1.31): https://masterofmagic.fandom.com/wiki/Hero

I don't know if/how your version might have changed things.

Whether you've hit a bug or whether you've just been unlucky is hard to tell without more information, such as how fast you're reaching the Summon Hero spell.

Fair enough. I am doing a game now where I am very specifically watching my gold for the 100g mark. I did see two heroes relatively quickly, so I was probably getting a bit unlucky and not monitoring my gold well enough.

Thanks

If I'm reading the wiki rules correctly, you need to float more than 100 gold to avoid missing opportunities. I'm not sure what order the game makes its checks before offering a hero.

If the game determines a hero arrives, then rolls for the hero among your available options based on fame (so Warrax wouldn't be in the pool of possibilities if you only have 5 fame), then compares that hero's gold cost against your current treasury, then you might not be getting offers because the game keeps trying to offer higher tier heroes and you keep failing the treasury check because you only have 100-ish gold versus their 200+ hire cost.

Similarly, if you missed a hero offer (say, Valana) because you didn't have enough gold, then you need to float more than 100 if that hero shows up again because they have a higher asking price to account for their higher level.

Assuming you are playing Caster of Magic, you need more than 100 gold.
Fame zero heroes cost 100-300 gold but fame 10-20 heroes can cost even more than that.
Also, in Caster of Magic, heroes start appearing on turn 30, but the chance of getting a hero offer is higher afterwards. As Famous increases the chance of getting a higher fame requirement hero and they might have additional levels, even more gold is necessary than usual, I recommend at least 600.

Even in Master of Magic 100 gold will not be enough to afford all the heroes, especially for fame 20. The game rolls which hero you will get first, then checks your gold and if it's too low, you get no offer.

Good information, thanks a lot!