Low-temperature pyrolysis is a promising route for valorizing underutilized tropical lignocellulosic residues into liquid, solid, and gaseous products under mild operating conditions. In this study, ulin wood powder and rubber seed shell were pyrolyzed individually and as blends at 300 °C in a fixed-bed reactor. The feedstock compositions were KU 100%, CK 100%, KU:CK 75:25, KU:CK 50:50, and KU:CK 25:75. The resulting products were evaluated using mass-balance analysis, Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), and scanning electron microscopy (SEM). KU 100% produced the highest tar/bio-oil yield, reaching 207 g or 41.40 wt%, whereas CK 100% produced the highest biochar yield, reaching 241 g or 48.20 wt%. The KU:CK 50:50 blend generated the highest gas fraction, 205.65 g or 41.13 wt%, indicating a non-linear redistribution of products during co-pyrolysis. FTIR analysis indicated enhanced aromatic character in CK-rich biochars, while GC-MS identified important volatile compounds, including benzene at 2.49 min, toluene at 3.58 min, and phenol at 7.09-7.21 min. These findings suggest that the feedstock blending ratio can serve as an effective, catalyst-free, and energy-efficient process variable for directing bio-oil, biochar, and gas production from local biomass through low-temperature pyrolysis.