avathara combining animals and humans stopped after a few avathars of God.
any ideas on how it started and why it stopped after a few avathars ?
Sorry for digressing from OP in the thread.
We have different list for avatars in addition to the common Dashavatar.
Twenty-two avatars in Bhagavata Purana:
Twenty-two avatars of Vishnu are listed numerically in the first Canto of the Bhagavata Purana as follows:
1) Catursana [SB 1.3.6] (The Four Sons of Brahma)
2) Varaha [SB 1.3.7] (The boar)
3) Narada [SB 1.3.8] (The Traveling Sage)
4) Nara-Narayana [SB 1.3.9] (The Twins)
5) Kapila [SB 1.3.10] (The Philosopher)
6) Dattatreya [SB 1.3.11] (Combined Avatar of The Trimurti)
7) Yajna [SB 1.3.12] (Vishnu temporarily taking the role of Indra)
8) Rishabha [SB 1.3.13] (Father of King Bharata)
9) Prithu [SB 1.3.14] (King who made earth Beautiful and Attractive)
10) Matsya [SB 1.3.15] (The Fish)
11) Kurma [SB 1.3.16] (The Tortoise)
12) Dhanvantari [SB 1.3.17] (Father of Ayurveda)
13) Mohini [SB 1.3.17] (Beautiful/Charming Woman)
14) Narasimha [SB 1.3.18] (The Man-Lion)
15) Vamana [SB 1.3.19] (The Dwarf)
16) Parasurama [SB 1.3.20] (The Rama with an Axe)
17) Vyasa [SB 1.3.21] (Compiler of the Vedas)
18) Rama [SB 1.3.22] (The King of Ayodhya)
19) Balarama [SB 1.3.23] (Krishna's Elder Brother)
20) Krishna [SB 1.3.23] (The Cowherd also Svayam Bhagavan)
21) Buddha [SB 1.3.24] (The Deluder)
22) Kalki [SB 1.3.25] (The Destroyer)
The idea of the messiah came to the western religions of Judaism, Christianity and Islam from the Zoroastrian religion of ancient Persia. Zoroastrianism has similar incarnations of Vrithragna (Indra). Hence it is related to the avatar idea of the Hindus.