Fire brand is a scimitar, Frost brand is a short sword.

This is partially in support of Orc players now having a racial
boost to scimitar skill, and partially to break up the mass of
artifacts that all are longswords.

libnethack/include/artilist.h

@@ -1,5 +1,5 @@
 /* vim:set cin ft=c sw=4 sts=4 ts=8 et ai cino=Ls\:0t0(0 : -*- mode:c;fill-column:80;tab-width:8;c-basic-offset:4;indent-tabs-mode:nil;c-file-style:"k&r" -*-*/
-/* Last modified by Fredrik Ljungdahl, 2017-11-02 */
+/* Last modified by Yer mivvaggah, 2017-11-13 */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -128,11 +128,11 @@ static const struct artifact const_artilist[] = {
       STUN(3, 4), DFNS(AD_MAGM), NO_CARY, 0, A_NEUTRAL, PM_WIZARD, NON_PM,
       3500L),
 
-    A("Frost Brand", LONG_SWORD,
+    A("Frost Brand", SHORT_SWORD,
       (SPFX_RESTR | SPFX_ATTK | SPFX_DEFN), 0, 0,
       COLD(5, 0), COLD(0, 0), NO_CARY, 0, A_NONE, NON_PM, NON_PM, 3000L),
 
-    A("Fire Brand", LONG_SWORD,
+    A("Fire Brand", SCIMITAR,
       (SPFX_RESTR | SPFX_ATTK | SPFX_DEFN), 0, 0,
       FIRE(5, 0), FIRE(0, 0), NO_CARY, 0, A_NONE, NON_PM, NON_PM, 3000L),