Ketu as ruler of Ashwini, Magha and Mula:Ashvini in Aries, sign ruled by Mars, combines energy of Ketu with Mars energy. Quality of such blender of energies gives a more emotional and expressive character. It is also a healing energy.
Magha in Leo gives a more personal energy, giving self-doubt and reflection on the past, like Ketu-Sun, that is why it relates to one's ancestors. Mula in Sagittarius gives a more spiritual energy, Ketu-Jupiter, but also doubt and karmic reckoning. Fiery planets rule Ketu Nakshtras, including by Mars, whose nature Ketu follows. Ketu does well if placed in its own Nakshatras.
Ashlesha in Cancer gives more emotional energy, like Mercury-Moon. Jyeshta in Scorpio gives a more vital energy and critical expression, like Mercury-Mars. Revati in Pisces has a more emotional and expensive energy, like Mercury-Jupiter. Generally, mercury doesn't do well when placed in its own Nakshatras because there are all inimical and watery signs. However, the spiritual and intuitive side of Mercury can come out of them, as can the emotional and deceptive side.