Two-dimensional　Cr-group　MXene　(denoted　M2CT2,　where　M　represents　a　Cr　group　transition　metal,　and　T　means　none　or　O/F　functionalization)　materials　sometimes　have　intrinsic　magnetism　and　metallicity.　Using　firstprinciples　calculations,　the　properties　of　Cr-group　MXenes　are　explored　using　atom-scale　analyses.　It　is　concluded　that　Cr2CT2　compounds　are　more　stable　when　spin　polarized　depending　on　the　case,　while　Mo2CT2　and　W2CT2　are　always　most　stable　without　magnetism.　Besides　structural　stability,　our　simulations　also　predict　charge　transfer,　metallicities,　battery　performances　(capacity,　charge-discharge　velocity),　and　thermoelectric　properties　of　Cr-group　MXenes.　Surprisingly,　Cr-group　MXenes　have　superior　natures　to　other　popular　energy　storage　materials.　Meanwhile,　Cr-based　MXene　(Cr2CT2)　has　unique　advantages　such　as　excellent　performance　with　lightest　weight.　Our　results　provide　insight　into　MXene　cognate　research.