Who is Vajrakilaya?

"The yidam we know as Glorious Vajrakumara, or Vajrakilaya, is the extremely wrathful form of Vajrasattva. This means that Vajrasattva is Vajrakilaya’s peaceful manifestation. Other manifestations of Vajrasattva are the semi-wrathful form known as Dorje Namjom (Vajra Vidharana) and the wrathful form known as Vajrapani.

Vajrakilaya is the physical manifestation of the power of the enlightened activity of all the sugatas of the three times. All enlightened activity gathered into one form is the deity Vajrakilaya. Therefore enlightened activity is the essence of Vajrakilaya."
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....Lerab Ling, 20 August 1997

The second paragraph is interesting if one recalls the legend of Kali and Durga. Copy of Vajrakilaya in Rumtek monastery painted on its wall