quemadmodum

Quemadmodum is three words fused into one: quem ad modum, "to which measure". Older texts still print it apart, and knowing that tells you why the accusative quem is sitting there with nothing to agree with. As a comparative conjunction it means "just as", usually answered later in the sentence by ita or sic, and it takes the indicative because it states a fact.

Its other job is to introduce an indirect question, "how", and there it takes the subjunctive: nescio quemadmodum fiat. Ecclesiastical writers lean on it hard for scriptural analogies, which is why it turns up far more often here than in Caesar. Quomodo is the shorter, later rival and slowly wins; Italian come and French comme descend from that one, not from this.