Complex sentence: At the same time, monsters appear in his town, and they attacking the citizen, Thouars entrusted him with attribute power and suddenly transform into twintail warrior girls, as known as Tail Red.
Split into simpler sentences: At the same time, monsters begin to appear in his town, and they start attacking the citizens. In the midst of the chaos, Thouars entrusted him with attribute power, thus suddenly transforming him into a twintail warrior girl, known as Tail Red.