Most of planets / objects in the sky have twofold nature: they are partially Yang, and partially Yin. The degree to which they are either one, or the other, varies for each of them. For instance, Mars is definitely more Yang, while Saturn is more Yin. There are two exceptions, however: the Moon, which is believed to be purely Yin, and Sun, being purely Yang. Chinese people assigned for these two also the world directions in the Ba-Gua scheme (8-fold scheme): water and fire, respectively. In this philosophy, water is receptive, while fire is creative.

If you look at the Leo zodiac sign, which is ruled by Sun, you may realize how much creativity is involved in it. Leo is a fixed sign, so while having lots of common with the other fire zodiac signs (Aries and Sagittarius), it also works differently: it places focus on a goal and is very determined in achieving it. While you can no doubt sense determination in Aries as well, the latter quickly abandons anything that is not achieved in one shot; it is even more true for the mutable Sagittarius sign. But it is not the case with Leo - not at all. With such a strong focus comes power cumulated in time, which sometimes is mistaken with a 'strong personality', but is an effect of the former.

Sun related energy is very general and very deep. It is also very universal, unlike all the other celestial objects. It can be used in many, many ways, and it seems there are no limitations for it. However, one needs to remember about its core nature: it is a very creative, warming and stable power.