Rulers of Houses in Houses

"Planets in a house carry a potential and may make things hard or easy, but the house ruler decides the way in which the potential is realized." – Karen Hamaker-Zondag, The House Connection
The Ruler of the Sun in Astrology

Each sign relates to a particular set of mythic figures, and each sign also has a planetary ruler or presiding deity with its own set of stories. The planetary ruler of the Sun sign can give us insight into the god who engenders the hero, for this planet, even more than the ruler of the Ascendant itself, may describe the kinds of situations the hero will meet on his journey. But the Sun ruler is our presiding deity; and the hero and his prize are ultimately the same thing.

— Liz Greene, The Luminaries: The Psychology of the Sun and Moon in the Horoscope (Seminars in Psychological Astrology)