It seems like the first tier upgrade to the Ymir altar is much more difficult than other religions. It takes 100 shards of ice, and then an additional 30 manifestations of zeal. Since you can get only 1 shard per humanoid kill, and each zeal takes minimum 5 shards, that means you have to kill a minimum of 250 humanoids, and that’s assuming you remember/have the opportunity to use your axe on them.
This is ridiculous. I can understand this amount when apparently the axe worked on trees, but with it now only being on humanoids, come on, this needs a huge rework! Contrast this to the others, were you need only ~30 kills.