There are two forms of Agni as Jataveda and Kravyada. Jataveda is invoked to burn and carry offerings except flesh to Gods and Kravyada is invoked to burn flesh. I am quoting definition from here.
Agni is said to have two forms Jataveda and Kravyada. As Jataveda, Agni is identified with Brahman and infinite knowledge and is invoked to burn and carry the offerings (except flesh) to the respective Gods. He is the pure form, the sacrificial priest and divine messenger who intercedes between humans and Gods and thus pleasing Agni, in turn, is said to please the Gods.
As Kravyada, Agni is obtained from the rays of the sun and is invoked to burn flesh (animal parts and corpses) in the Pitru Yajna. It is the fire of the funeral pyre and hence as such is said to be the impure form which is much feared.
Rig veda say the same thing as:
करव्यादमग्निं पर हिणोमि दूरं यमराज्ञो गछतुरिप्रवाहः |
इहैवायमितरो जातवेदा देवेभ्यो हव्यंवहतु परजानन ||
यो अग्निः करव्यात परविवेश वो गर्हमिमं पश्यन्नितरंजातवेदसम |
तं हरामि पित्र्यज्ञाय देवं स घर्ममिन्वात परमे सधस्थे ||
यो अग्निः करव्यवाहनः पितॄन यक्षद रताव्र्धः |
परेदुहव्यानि वोचति देवेभ्यश्च पित्र्भ्य आ ||
9 send afar flesh eating Agni, bearing off stains may he depart to Yama's subjects.
But let this other Jātavedas carry oblation to the Gods, for he is skilful.
10 I choose as God for Father-worship Agni, flesh-eater, who hath past within your dwelling,
While looking on this other Jātavedas. Let him light flames in the supreme assembly.
11 With offerings meet let Agni bring the Fathers who support the Law.
Let him announce oblations paid to Fathers and to Deities.