Complex sentence: Stela 15 shows K'inich Yat AhkII as a devout practitioner of religious rituals, doing his sacred duty, whereas Stela 12 shows the "ajaw" as a victorious military chief, defeating enemies and taking captives.
Split into simpler sentences: Stela 15 shows K'inich Yat AhkII as a devout practitioner of religious rituals, doing his sacred duty. On the other hand, Stela 12 shows the "ajaw" as a victorious military chief, defeating enemies and taking captives.