Error-prone polymerase lacking a proofreading 3'-5' exonuclease which catalyzes the gap-filling reaction during the DNA repair process (PubMed:11685239, PubMed:28245220). Specifically binds intermediates in the single-nucleotide base-excision repair process (PubMed:12595253). Also catalyzes DNA polymerization with low nucleotide-insertion fidelity (PubMed:24617852). Probably acts as a strategic DNA mutase, which gives rise to a rapid emergence of variants (PubMed:11685239). Generates mismatched G-G pairs, in that case, the polymerase first binds the deoxynucleotide followed by mismatch formation (PubMed:24617852). Together with the viral DNA ligase, fills the single nucleotide gaps generated by the AP endonuclease (Probable). Binds DNA with high affinity via the helix alphaE (PubMed:24617852). a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) In the presence of magnesium, pol X shows a strong preference for the ssDNA gaps having one and two nucleotides. Found in association with viral nucleoid. Small DNA polymerase formed from only a palm and a C-terminal subdomain (PubMed:11685239). Unlike other polymerases, binds DNA via the helix alphaE (PubMed:24617852). The total DNA-binding site of pol X is composed of two DNA-binding subsites. Consistent with its intracellular location, ASFV encodes its own replicative DNA polymerase and three base excision repair enzymes: a class II AP endonuclease, the repair polymerase Pol X, and an ATP-dependent DNA ligase. Belongs to the DNA polymerase type-X family.