Hindus - Which devi becomes Kundalini shakti ?

KundilinI is the ultimate energry of Mahashakti Prakriti. It is not wise to connect them with its any manifestation like Saraswati, Kali or Lakshmi. Generally this MahaShakti is situated in the root of Mooladhaar Chakra, coiled in three and half circle round ShivaLingam, it is head is down and tail is kept in its mouth.

iT is given many names by Yogis and Siddha like Kundalini, Bjjangini, Sarpini, Prachanda Shakti, Mooladhaar Nivaasini, Valayakaar Sarpini, Vidyut, AgniMay, MuktaShakti, Mahadevi, SaptaChaKra Bhedini, VishwaShakti, Vidyut Pravaah Roopini, Sarva Saundarya Shalini, Sarva Sukh Dayini, Aparaajita, Vishatantuswaroopa, MoolVidya, KutilRoopini, NavaShakti Samanvita, Shakti Chalita, Adhomukh Sarpini, Krivalyaa, Shabda Brahmamayi, NavChakratmika, Bhujangaakar.

IF you study the each name properly with their sanskrit meaning, you will find that kindilini is irrespective of any Saakar form. Sakar forms are used to meditate. While rest of the path goes with pure quest of the MahaShakti.

EDIT::AVR:: Read Purans, Upanishadas and many other scrptures who are like genuine Bhashyas on Vedas, All have the concept of Kundalini, Yog and Pranayaam. This is how we can divert our attention towards Him and WE CAN COME IN THE PROCESS OF ETERNAL AND INFINITE SPIRITUAL PROCESS.

Since it (Shakti) unites with Shiva, it has to be Parvati, Shiva's wife.

Parvati is Shakti's (i.e. the Divine Feminine's) second incarnation as wife to Shiva. After Shiva's first wife, Sati, died, Her divine body parts were strewn all over India (all the places where parts landed became Shakti pithas, or "seats of the Goddess," which are now sites of Devi temples) -- and Shiva completely turned His back on the world, resuming the life of an ascetic in a remote Himalayan cave, while the demon Taraka overran the heavens and earth below.

With no "living" Shakti (manifest Divinity) to balance Shiva (transcendent Divinity), the Cosmic order was thrown into disarray: Shiva had no interest in the world, and in any event was "powerless" (Sanskrit Shakti = Power, Energy) to help it. And so the gods prayed to Shakti to incarnate once again and turn Shiva back to the world, thereby restoring Cosmic balance and saving the world. Shakti agreed, and thereupon took birth as Parvati, Daughter of Himavan, Lord of the Mountains.

Kundalini shakti is not due to any Devis. It is a universal Power which starts from Muladhara Chakra and moves upto Shasrara Chakra through Sushumna Nadi. Union of Shiva and Shakti is achieved that time.

As per my knowledge

If Shiva represents Soul, then Shakti must represent his power. The soul's power, or the cosmic energy responsible for creation. I have seen that each chakra has a presiding god and goddess. But the kundalini is the sum total of all energy. She is Adi para shakti.

Kundalini shakti is the form-less life force present in the dormant state in every being of this universe irrespective of the cast, religion, culture and the region.

So I think, it should not be related to any particular divine being.

With a little change in Arya's answer :

Kundalini shakti is the manifestation of ADI-Shakti ! a sum of all energies including MahaSaraswati + MahaLaxmi+MahaKali

Kundalini Shakti is all of creation and the creation process itself.

Parvathi .Kundalini is the manifestation of Adi Shakthi Parvathi

shakti. when the kundalini shakthi unites with Lord shiva. so, it is parvathi. we can say as Lakshmi or Durga. Generally we say as shakthi.

Kundalini Yoga is a tantric practice that is supposed to release the practitioner's own energy, which otherwise remains quiescent.

In my opinion it just diverts the attention from realization and probably best avoided.