पितृस् are a set of demigods. From मनुप्रजापति , son of ब्रह्मा , were born the सप्तर्षिस् like मरीचि and they in turn created the पितृस् . Besides मरीचि and his set many others like विराट् पुरुष and ब्रह्मा have created पितृस् . Some पुराणस् state that पितृस् are of daily creation. ब्रह्मा in the beginning created three sets of पितृस् with form and four with brightness making thus seven sets. The three sets of bodied पितृस् are अग्निष्वात्तस् , बर्हिषदस् and सोमपास् and the four bright ones are यम , अनल , सोम and अर्यमन् (10th Skandha, Devī Bhāgavata) .

मनोर् हैरण्यगर्भस्य ये मरीच्यादयः सुताः / तेषामृषीणां सर्वेषाम् पुत्राः पितृगणाः स्मृताः " // (śloka 194, chapter 8, manusmṛti) . Pitṛs (manes) are c

सोमसदस्य (s)

विराट् पुरुष is the creator of these पितृस् . सोमसदस्यस् are the पितृस् of साध्यदेवस् .

अग्निष्वात्त (s)

They are the पितृस् of देवस् .

बर्हिषदस्

These पितृस् are the creation of the sage अत्रि . They are the manes of दैत्यस् , दानवस् , यक्षस् , गन्धर्वस् , उरगस् (serpents), राक्षसस् (demons), सुवर्णस् and किन्नरस् .

सोमपा ( s )

They are the sons of the sage भृगु and are the manes of ब्रह्मिन्स् .

हविर्भुक् (s)

The sage अङ्गिरस् is the father of these पितृस् who are the manes of क्षत्रियस् .

आज्यपा ( s )

These are the sons of the sage पुलस्त्य and are the manes of वैश्यस् .

सुकालिक (s)

Sons of the sage वसिष्ठ , these पितृस् are the manes of the शूद्रस् .

To the seven sages like मरीचि were born the पितृस् and to the पितृस् were born the देवासुरस् (devas and asuras) and to the देवासुरस् were born everything else in this universe, animate and inanimate. (Chapter 3, Manusmṛti) .

Performing a श्राद्ध (offering obsequial oblations to the departed) is just like a yajña. The oblations should be offered in either silver or silver cum copper pots. विश्वदेवस् are the guardians of the पितृस् . Therefore the oblations should be offered after worshipping the विश्वदेवस् first and then the पितृस् and then विष्णु . (See under Śrāddha) .