That's what the tax revenue from the fort is for, combine that with some colosseum winnings and the rewards from the adventure and I'm sure it's enough...barely. Good thing the cost of living in the Frostmarches is so low. Luckily you don't really need to pay for the Kiyoko kits since they've got their own homestead type thing. Being stuck as a Colosseum warrior to pay off child support is a hell of an ending though.
It's a little hard to get a maximum count but even not counting Kiyoko kits, assuming you impregnate every character you can once (since it's unlikely any non-harpy pregnancy ends before the game does) and they have the maximum number of children possible you easily end up with something in the ballpark of 50 kids, and this isn't counting generic npcs and enemies.
Apparently it takes 15k electrum to raise a child in a Mallachite temple for 18 years. And that’s apparently a very comfortable, educated upbringing. So, let’s say a child is going to cost 600 EC on average; most of champ’s children are realistically not going to learn anything beyond basic reading and writing, maybe, if that, so probably even less than that. Harpy and orc children probably not even getting that in terms of education. Let’s also say that, at 1000 EC per 10 days, 36,000 per year (lowball; didn’t feel like using non-round numbers lol) 60 children can be supported. I have no idea how many children my champ has by this point total, so those calculations are kind of pointless, but it’s probably going to be much, much, higher than 60. So yeah, it’s either the colosseum, hiding out in the Ways Between, or getting lynched horrendously.